BLlLLETIN 

OF THI<: 

ILLINOIS STATE LABORATORY 


OF 

NATURAL HISTORY 

URBANA, ILLINOIS, C. S. A. 

VOL. VII. SEPTEMBER, 1909 

'l'HE ORIBATOIDEA OF ILLINOIS.
• 

BY 

HENRY E. EWING, A.N\. 



ERRATA AND ADDENDA.

Page 35, line 15, for 1854- read 1855.

Page 55, line 16, for Horticultural read State Agricultural.

Page 60, in second table, Illinois, for 240 read 241.

Page 65, first line above foot-note, for ventricosa read ligamentina.

Page 72, line 9, for imhecilis read imbecillis.

Page 79, line 19, for asperimus read asperrimtts.

Page 80, above Quadrula rubiginosa insert Section Fusconaia Simpson.
Page 76. The record of Calkins for Margaritana margaritifera is without

doubt erroneous and should be eliminated. This species is not found in Illinois.

Page 95. Pomatiopsis sheldonii Pilsbry should read Amnicola sheldonii and
should be transferred to the genus Amnicola on page 93.

Page 100. Physa gyrina oleacea Tryon is the immature stage of Physa gyrina.

Page 103. Lymncsa tazewelliana is a synonym of Lymncea parva.

Page 105. Lymncea palustris michiganensis is the immature form of Lymncca
rcflcxa.

Page 106. Lymncza reflexa ioivensis and Lymncea reflexa crystalensis are

synonyms of Lymncea reflexa.

Page 112, line 6 from bottom, for goitldi read gouldii.

Page 114, line 5 from bottom, for jnxtigcns read juxtidens.

Page 115, line 21, for Witter read Walker; line 23, Polygyra sayii Binney should
be changed to Polygyra sayana Pilsbry.

Page 116, line 1. Polygyra exolcta Binney (1885) should be changed to

Polygyra zaleta Binney (1837).

Page 117, line 11 from bottom, for Icai read leaii; line 3 from bottom, Poly-
gyra monodon fraterna is a good species and should read Polygyra fraterna.

Page 119, foot-note. A specimen of alliarins in the collection of Mr. Aldrich,

received from Calkins, proves to be draparnaldi.

Page 121, line 3 from bottom, for Champaign read Piatt.

Page 122, line 12 from bottom, for Pyramidula siriatella Anthony read Pyra-
midiila cronkkitci anthonyi Pilsbry; line 4, for Held read Hald.

Page 123, for Helicodiscus lineatus Say read Hclicodiscus parallcliis Say.

Page 162, line 7, for glandulosa read linearis.

Page 171, line 17, for riparia read vulpina.

Page 176, line 8 from bottom, for canadense read majiis.

Page 180, line 9, for virginica read virginiana.

Page 221, line 6 from bottom, for rectangiiliis read rcctangttlaris.

Page 226, line 3, for fasciatus read fasciata.

Page 239, line 11, strike out Lake Co. entry.

Page 246, lines 6 and 7, and page 248, lines 1, 14, 20, and 23, for CEnothera
read Onagra.

Page 248, line 4, for Candida Horn substitute n. sp.



Pac^e 249, line 8 from bottom, for Olethreutes dimidiana Sodoff? read

Olethreutes separatana Kearfott, and strike out parenthetical matter.

Page 251, line 7, for grossa read thoracica; line 21, for words preceding H. 6,

read Asilus rufipennis Hine; line 18 from bottom, for words preceding H. 2, substi-

tute Asilus cacopilogus Hine.

Page 253, line 8, for Linn, read Emory.

Page 257, line 15, for pennsylvanicus DeG. read auricomus Rob.

Page 261, Note 6. Melanoplus macneilli is very probably M. ftuviatilis Brun.

Page 262, Note 9. Dr. Bergroth writes that Nabis elongatus is preoccupied.

The original is elogantus in the check list. Comparison with long-winged vicarius

is desirable before re-naming it.

Page 309, in table, for 59 read 57, and for 743 read 741.

Page 310, in table, for JS* read 57.

Page 314, line 5, for 1587 read 481; line 16, after stubble insert meadows; line

17, after pastures strike out and meadows, and after 1600 strike out each.

Page 315, last line, for 553 read 481.

Page 362, line 7 from bottom, for longa read parvilamellata.

Page 373. As a second entry in synonymy insert as follows:

1854. Nothrus bistriatus, Nicolet, Acariens des Environs de Paris, p. 397,

PI. VII., Fig. 7.

Page 376, line 13 from bottom, for Oribata read Oribates.

Page 378, line 1, for XXV. read XXXV.
Page 384, after line 5 insert as follows:

N. bipilis Hermann. Mem. Apt., p. 95.

In moss. Areola and Parker, 111.

Page 384, line 5 from bottom, for pyrostigma read pyrostigmata.

Page 386, after line 11 from bottom insert as follows:

H. bistriata Nicolet. Acariens des Environs de Paris, p. 397, PL VII.,

Fig. 7.

Under logs and in moss, Urbana and Areola, 111.

Page 388, line 12, for sphcerulum read sphcsrida.



Article X.—Thc Oi-ihatuidea of IUiii()i». By Henry. E.

EwiNG.

. Introduction.

The mites of the group Orihatoidea, though abundant in

this country, have received but little study. About a hundred

species have been recorded from America. Out of this

number over 90 per cent, are new species, yet with this very

large per cent, of new species only two new genera (Gi/iinio-

bates Banks and Tin)iidoIn(s Ewing) are peculiar to our country.

Our fauna is especially rich in the abdominal-winged forms

{Pferor/asferea). The number of the Pterofjasfeira described

from this country, up to the present, is over 40. Nearly all of

these winged forms have a shiny integument, which fact may
have caused their more ready discovery and the apparently

much greater percentage of winged forms here than in Europe.

The Orihatoidea are appropriately called beetle-mites be-

cause of their hard, chitinized integument. They are quite

distinct however from the mites of those groups which are para-

sites or pseudoparasites of beetles, and which for this reason have

been called beetle- mites by some persons. The internal anatomy
and life history of this group have been studied very carefully

by A. D. Michael, of England, to whom the writer is indebted for a

large collection of named European species. The physiology

and embryology of the group are almost entirely unknown.

Economically the beetle-mites have no great importance.

The writer is very much indebted to Dr. J. W. Folsom, of

the department of zoology of the University of Illinois, for

assistance in many ways. Mr. J. D. Hood, a specialist in the

study of the Thiistdiopfcru, has not only collected material for

the author from many parts of the state, but has in most cases

furnished mounted specimens and also added notes npon their

337



338

habits, etc. The following persons have aided very materially

in collecting specimens: Mr. C. A. Hart, systematic entomol-

ogist of the State Laboratory of Natural History; Mr. J. J. Davis,

assistant to the State Entomologist; Mr. J. L. Pricer, A. M.,

graduate student in entomology; and Messrs. J. Zetek, R. D.

Glasgow, and H. Glasgow, all students of the University of

Hlinois,

Dr. S. A. Forbes has kindly permitted the author to work
up the oribatid collections of the State Laboratory of Natural

History, in which type specimens of the species described in

this paper have been deposited.

Methods.

In making collections of oribatids several methods may be

employed. It is very desirable that these mites be collected

alive, in order that they may be studied before being placed in

a preserving fluid. All notes on color and the position of the

bristles and pseudostigmatic organs should be made from living

specimens. Individual mites can be very readily transferred

on a camel's hair brush to a collecting vial, to be taken to the

laboratory and killed.

Specimens are best killed in hot water or hot alcohol, when
they die in an extended position, most favorable for study.

While the specimens are still in the alcohol, notes should be

made on the shape of the pteromorphie, the pseudostigmata,

and the pseudostigmatic organs, since it is hard to study the

form of these parts in the dorsal or ventral view of perma-
nently mounted specimens. Mr. Michael suggests the use

of dilute acetic acid instead of alcohol as a preservative.

In order to collect oribatids in large numbers, I use with
great success a moditication of the Berlese method described

by Howard in "Entomological News", Vol. XVII., 1906, pages
49-54. If vegetable debris is passed through a sieve before

being treated by the Berlese method, the number and variety

of small arthropods that may thus be obtained is surprisingly

large. A simple but satisfactory method consists in placing



839

Ps.Os.

the siftings on a. Hat dish suspended over a large funnel, and

placing the funnel and all in the sunlight. The sunlight drives

the mites out of the siftings, and they fall through the funnel

into a vial below.

The most convenient and satisfactory mounting media for

oribatids are Canada balsam and dammar balsam. Dissections

of the month-parts are frequently necessary. Material must

often be rendered partially transparent by means of potassic

hydrate or eau de Labrraque.

In making the drawings I used an Abbe camera lucida.

The measurements were made with an ocular micrometer.

External Anatomy.

The body in the Oribatoidca (Fig. 1) consists of an anterior

narrower region termed the

cephalothorax, and a posterior,

much larger, portion termed

the abdomen. The union of

these two regions is more in-

timate in some genera than in

others. There is usually an

evident division between the

cephalothorax and the ab-

domen except in the genera

Scutorcrtc.r and Anicnis. In

two genera, llDphxIcniKi and

PhthirdcdfKs, the cephalo-

FiG. 1. z>a//(.t7(.s /('7('/(.s, dorsal view. tliorax IS hinged to the ab-

domen in such a way that the former can be folded down

against the ventral surface of the latter.

The cephalothorax may be divided into - ^'^•''•

two parts; the rostrum (Fig. ], 7^.) and

the posterior portion. The rostrum is the

anterior hood-like portion wdiich protects

the mouth-parts. Upon the rostrum is

found a pair of stout hairs termed rostral
^^^^^ orii.,ta Und-si,^^^,.

hairs (Fig. 1, H'k //.); sometimes the dibie.

lit seg-



340

Max.l.

rostrum bears an additional pair of hairs. Underneath the

rostrum may be seen the mouth-parts, which consist of man-
dibles (Fig. 2), palpi (Fig. 3, Pa.), maxillae

(Fig. 3, Ma.r.), and the maxillary lip (Fig. 3,

Max. L). From the maxillary lip project the

maxillsB and the palpi. The maxillae are

curved and blade-like, and are large and
highly developed in the genus Hoploderma.

The palpi consist usually of five segments,

and as a rule are very small; in the genera
Phth'u-acanis and Hop/odertna, however, they

are large. On the posterior part of the

cephalothorax are found the following

organs: pseudostigmata, pseudostigmatic

organs, lamellae, lamellar hairs, interlamellar

hairs and sometimes a translamella, and often one or more
pairs of tectopedia. The pseudostigmata (Fig. 4, Ps.), formerly

supposed to be the true stig-

mata, are situated near the

abdominal margin and usually

close to the lateral margin of

the cephalothorax. They are of Fig, 4.

various forms, though usually

cylindrical or funnel shaped.

Fig. 3. Oribufu baukf>

mouth-parts.

iPsorg.

Oribata setDm, pseudostigma and
pseudostigmatic organ.

From each pseudostigma pro-

jects the pseudostigmatic organ (Fig. 4, Ps. org.). This may
be filiform, fungiform, setiform, clavate, or subglobose, and is

often pectinate or dentate. The lamelUe consist of either

blade-like chitinous projections, or of mere ridges. They
vary greatly in size and shape, and are situated on the

dorso-lateral part of the cephalothorax. Sometimes the la-

mellae project in a free end which may extend to the apex of the

rostrum or even beyond it. From the tip of the lamellae pro-

ject a pair of prominent bristles, termed the lamellar hairs.

The tectopedia, of which there may be as many as three pairs,

are generally blade-like, are situated on the sides of the

cephalothorax, and have either a tactile function or serve

to protect the coxae.



841

The abdomen has the following structures: dorsum, ven-
tral plate, anal covers, genital covers, often pteromorphir, and
sometimes large bristles. The dorsum of the abdomen consists
of a single large chitinous plate. The ventral plate varies
much in size; is sometimes confluent with the dorsum, and
contains the genital and anal apertures. The genital aperture
is anterior to the anal aperture, and is closed l)y two chitinous
"folding doors", known as the genital covers. The anal aper-
ture is similarly closed, its "folding doors" being termed the
anal covers. Sometimes on the dorsum, rarely on the ventral
plate, long bristles may be found, though frequently the ab-
domen is hairless. In some genera, as Pe/ops and Orilxtfa, there
are chitinous wing-like expansions of the abdomen termed
pteromorphii^ (PI. XXXI II., Fig. ^,pter.).

The legs (Fig. 5) consist of five

segments, namely, coxa, femur,
genual, tibia, and tarsus. The
coxa (Co.), or basal segment, is

usually the shortest and stoutest
Fig. 5. Orihata mol/iroiiKi, lear 4. j? i.i i i , •

ot the segments, and sometimes
has a blade-like expansion (/>V.) on one side. The femur ( Iu\)

is usually the largest and sometimes the longest segment. The
genual (Ge.) is very small and inconspicuous. The tibia (7"/.)

is usually subequal to the tarsus (7V/.), and often bears, espe-

cially on the front pair of legs, a long tactile hair at its distal

end. The tarsus ends in either one (monodactyle) claw or

three (tridactyle) claws, and never in two except in the

species Nof/irus aiKfimieiisis.

The parts most used for systematic purposes are the

pseudostigmatic organs, lamellae, translamella, pteromorphae,

and ungues.

Internal Anatomy.

Most of the internal organs of the oribatids may be divided

into three systems: the digestive, tracheal, and reproductive

systems. The digestive and reproductive organs occupy most

of the body cavity.



342

The digestive system includes tiie month, pharynx, oesoph-

agus, ventriculus or stomach, intestine, and rectum. The

mouth leads into a not well marked off region, called the

pharynx, which is sometimes broader than the oesophagus.

The posterior end of the cesophagus is generally enlarged, form-

ing the ingluves just in front of the stomach. The ventriculus,

or stomach, is very large, and its outline can often be seen

through the integument of light-colored species or in specimens

which have recently emerged from the nyaiphal skin. I have

found that treatment with acetic acid and mounting in glycer-

ine will frequently show the internal organs very plainly. The

stomach is almost like a spherical bag in most cases, with

its anterior wall lying at the division betw^een the cephalo-

thorax and abdomen, while its posterior wall extends to a point

almost above the anal opening. Extending out from the

stomach on each side at the posterior part is a blind pouch or

coecum. The coeca vary somewhat in size, shape, and situation

with the species. The intestine and rectum are very short and

often resemble a C-shaped tube, leading from the posterior wall

of the stomach to the anus. In connection with the digestive

process is a small pair of glands situated on the front wall of

the ventriculus or stomach.

The tracheal system exists only in the adult forms and is

absent in the IlopJodermidfe. The tracheae usually consist of

from eight to twelve main trunks, w^hich start from the acetab-

ula of the legs, most of them extending backwards in a wavy
course to the posterior end of the abdomen, where they become
slightly enlarged at their termination to form air-sacs. The
tracheae are always un branched.

The nervous system has not been w^ell worked out in the

case of the Orihutoidpa but consists of a sub- and a supra-

oesophageal ganglion, which have nerves running to the

important organs.

Situated on the sides of the abdominal cavity in the case

of some species, is a small sac which opens to the exterior

through the integument. This apparatus is supposed to have
an excretory function. The region of the cephalothorax is

largely occupied. by muscles controlling the legs and the mouth-



343

parts. No circulatory .system has been demonstrated in the
l)eetle-mites although some Ararina have a pulsating organ
called the heart.

The reproductive system occupies a large part of the lat-

eral and posterior portions of the abdomen. In the case of

the male, the organs consist of a large central gland, the testis,

which has two ducts, the vasa deferentia, leading from it. These
unite to form the ejaculatory duct, which opens through a

small penis. The reproductive organs of the female consist of

a paired or unpaired ovary, and of two large oviducts which
pass backwards along the sides of the abdomen to its

posterior end, to form there the vagina, which opens to the ex-

terior through a large protrusiljle ovipositor. The ovipositor is

usually trifid, and may possess a few small hairs on its distal

end. In specimens treated with glycerine and acetic acid, the

large ovipositor may often be seen in repose with its proximal
end against the posterior wall of the abdomen and its distal

end at the entrance of the genital opening.

Life History.

Most Oy'ihdtoitlfa are oviparous; some species, however, ac-

cording to Michael^ are ovoviviparous, and a few viviparous.

It is believed by some that many if not all the Orihatoiilea are

parthenogenetic. Up to the present time they have never been

found in copulation.

The larva:, as in the case of most of the Acki-'dki, have only

three pairs of legs, which always have tarsi with monodactyle

claws.

When the larva^ transform into the nymphs they have the

full number of legs of the adult, but in other respects are very

different from the mature forms. Instead of being a dull

brown or black color, they frequently are tinted with red, yel-

low, or pink, and, more marked yet, their external form may
be very different from that of the adult. Instead of having a

body almost or quite free from any integumentary projections,

as is generally the case in the adult, they may have large, leaf-

like, or sword-shaped integumentary processes. These integu-



844

mentary processes are sometimes so large that they almost

completely conceal the rest of the body. In the case of

the nymphs of some of the species of Liaranis, the leaf-like

appendages are radially arranged around the central part of

the body, giving the whole creature a beautiful stellate ap-

pearance. In the nymphal state the integument is usually

poorly chitinized. As would be expected, the sexual organs

are not developed in the case of the nymphs.

About ten days are passed by the inert nymph preliminary

to the appearance of the adult. Upon the splitting of the old

nymphal skin the adult usually emerges, leaving its "old

clothes " behind ; but this is not always the case, as is shown

by the genus Neoliodes, the members of which carry through-

out life the cast nymphal skin—which can readily be removed

by treatment with potassium hydroxide. The members of

the genus Danueus almost always bear a part of the old

nymphal skin supported by means of the bristles on the dorsum

of the abdomen, but not adhering firmly to the newly formed

integument as in the case of the species of Neoliodes. The
adults immediately after emerging from the nymphal skin are

usually lighter in color than the older forms ; in other respects

they are the same.

Habits.

The Orihatoidea are very small creatures of about the size

of a pin-head, or even smaller. They may be easily found

under logs (slightly decayed), under bark, in rubbish, under

stones, in moss, or may be shaken from the branches of trees

or collected in grass sweepings. They live v^ery largely upon
fungi, or, to some extent, upon plant juices, and apparently are

never predaceous although the Rojjiodennidw have large and
powerful mandibles. Most of the beetle-mites, though blind,

are very sensitive to light, and avoid it when possible. I have
found that they have a very sensitive touch and also have the

power of smell, which sense may be situated in the so-called

pseudostigmatic organs.



345

Not being well armed for aggressive warfare, this group is

very remarkable in its adaptation for defense. The thick chi-

tinous integument of the group when taken into consideration

with the special structures of the Oril>ati(J(i\ the pteromorpbub

or abdominal wings, affords an excellent protection against some
of their smallest, though most troublesome, enemies. When the

least disturbed, most of the species with these chitinous ab-

dominal wings will fold the legs up underneath the body and

close down the abdominal wings over them, so that they are

almost or quite completely concealed and protected. In case

of the Hoj)/o(Jeni(id(P, which have the cephalothorax hinged to

the abdomen, they at once feign death upon being disturbed,

fold themselves into a small ball by bending the cephalothorax

down over the ventral surface of the abdomen, at the same

time drawing up the legs, and are thus completely covered by

the cephalothorax.

In their movements the OrilxdohJcd are sluggish as com-

pared with the other Acarina. As a rule the smooth, shiny

species are more active than the larger, rough species. The

species of the genera Keoliodrs and Nofhnis are especially slow

in their movements. One species, Zetoir/H^sfes uiicronijclins,

w^hich though common in Europe has been found in only one

place in America, is quite unique in being the only oribatid

which is saltatorial.

Many of the OriOafoidea pass the winter in moss. Some
of the species which live upon the leaves of trees, apparently

winter under the bark.

The Taxonomy of the Higher Groups of the Oribatoidea.

Michael, the expert acarologist already mentioned, regards

the group of beetle-mites as a family, and in his monograph

of them in " Das Tierreich" (Lief. 3, 1898) divided the group

into seven subfamilies. I can hardly agree with this author in

all respects as to this division, for although the characters

which separate some of his subfamilies are fundamental and are

correlated with differences in habit as well as structure, others

are somewhat variable and hardly of more than generic im-



346

portance. I refer for example to the separation of his subfam-

ily Notaspi(Jin(r from the subfamilies D(nn(f'lnw and Nothrimt,

based upon the absence or presence of the lamellae. While the

laraellse are sometimes very constant in their shape and size in

a single species, yet, taking all the species together, we can get

an insensible gradation from forms with enormous shelf-like

expansions, which conceal much or most of the cephalothorax

from above, to small chitinous ridges or only wrinkles of the

integument which may vary in some cases so as to be almost

invisible. This fact, taken together with the fact that there

are few if any supplementary characters in support of

this division, make it rather artificial, if not unwarrantable,

to accord it the same rank with his other divisions of

the group. On the other hand, his separation of those forms

which have the cephalothorax anchylosed to the abdomen

from those which have the cephalothorax hinged to the same

(his Phthiracarin(e) is certainly based on characters of family

portance. This is more convincingly evident when we con-

sider the other important points of difference, which are given

below.

Forms with Cephalothorax An- Forms with Cephalothorax

chylosed to Abdomen. Hinged to Abdomen.

Body frequently depressed. Body always compresed.

With trachea3. Without trachea?.

Ventral plate anchylosed to Ventral plate not anchylosed

dorsal plate to dorsal plate.

Genital and anal openings sit- Genital and anal openings us-

uated apart. ually together

Legs frequently long or slender Legs always stout,

or moniliform.

Mouth-parts very small, or Mouth-parts large, mandibles

rudimentary. enormous.

Palpi with five segments. Palpi with only four segments.

Femora generally stouter than Femorasubequal in width tothe

the other segments of the legs. other segments of the legs.

Cephalothorax never with a Cephalothorax often with a

median carina. median carina.



347

Abdomen never with a chitin- Abdomen sometimes with a

ous hood-like projection from its chitinous hood-like projection

anterior margin. from its anterior margin.

Claws of legs usually small and Claws of legs always stout; if

monodactyle ; if tridactyle the tridactyle the dactyles are sub-

dactyles are usually unetjual. equal.

When we consider all these points of difference, it appears

to us that they are not only of sufficient importance for the

separation of the two forms into different families, but that

they might even justify a wider separation and a higher rank.

About the only important characters the two have in common
are the chitinous integument and the presence of the pseudo-

stigmata and the pseudostigmatic organs. Mr. Banks, in his

treatise on "The Acarina, or Mites" (Proc. U. S. Nat. Mus.,

Vol. XX VIII., p. 1-114), separates those forms which have the

cephalothorax hinged to the abdomen from the other oribatids,

under the family name of IlopJodermida'. This separation

and name the author of this paper has adopted.

Mr. Michael's separation of those forms which possess ab-

dominal wings from those which do not {''Apfcrofjdstcrea'") we

accept, raising both forms, however, to family rank, and giving

the first-mentioned the old name Oribafidw, since it contains

the old genus Orihata. This division is not altogether happy

fortworeasons: first, many authors may consider thesmall, shelf-

like chitinous expansions from the shoulders of the a))domen

in the case of some genera (as Xofaspis and Teijcocrnmoi) as

homologous with the true abdominal wings, or pteromorph*;

second, there are not many other fundamental characters in

support of the division. Notwithstanding these facts, we con-

sider the development of abdominal wings—especially when

takinginto account their defensive value and the habits of mites

possessing them, and some other points of difference as well

—

as of sufficient importance to entitle such forms to family rank.

Since we have applied the family name Oribat'dhc to those

forms having abdominal wings, the remaining forms, the ''Ap-

tf^nxpisferea'', we naturally consider as constituting a family, us-



348

ing for it the name NofJtrifhe, derived from the genus Nothrus,

which name has been previously so applied by G. Canestrini and

made a subfamily name by Mr. Michael.

Having thus created three families out of the group to

which the old family name Orihatidw was given, we regard the

group as a superfamily, as suggested by Mr. Banks, including

in it, however, as already stated, three families for the tw^o

{Orihatidce and Hoplodermidw) recognized by that author. The
following is a summary of the characters of the superfamily

Orihatoidea:

Integument generally well chitinized, which gives the in-

dividuals a beetle-like appearance. Cephalothorax with a pair

of funnel-shaped or cylindrical structures on the dorsum which

are called pseudostigmata, from each of which projects an

elongate specialized organ, or seta, the pseudostigmatic organ;

chitinous blade-like expansions termed lamellae often present.

Palpi small, with five segments, generally hidden by the ros-

trum; mandibles chelate. Abdomen usually oval; ventral

surface covered by a large chitinous plate termed the ven-

tral plate; dorsal surface often with a large chitinous wing-

like expansion on each side, known as the pteromorpha. Legs

composed of five segments, the distal segment bearing a claw

(unguis) which is either monodactyle or tridactyle.

KEY TO THE FAMILIES OF ORIBATOIDEA.

1. Cephalothorax and abdomen immovably fused together;

body never compressed; mouth-parts small; with tracheae

opening at the acetabula of the legs; legs often long or

slender 2.

Cephalothorax hinged to the abdomen and capable of being

folded down over the ventral surface of the same; body

compressed; mouth-parts large; without tracheae; legs

stout , HOPLODERMID^.

2. Abdomen possessing chitinous wings, or pteromorphae; integ-

ument usually smooth and shiny and always well

chitinized; legs never stout or with swollen seg-

ments Oribatid^.



349

Abdomen without wings; integument often rough or sculp-

tured and sometimes very little chitinized; legs fre-

quently stout or moniliforni Nothrid^.

The three families of the superfamily Or/ hafolder we
divide into 29 genera, which are distributed as follows: Ori-

h(dl(Ja', 5 genera; yothridn', 21 genera; and Hoplo<leruiidn% 3

genera.

KEY TO THE GENERA OF ORIBATIDiE.

1. Superior bristles of body spatulate; mandibles long and

slender; integument sometimes rough or pitted. . Pelops.

Superior bristles never spatulate; integument smooth. .. 2.

2. Tarsi of first pair of legs broad at the tip; pteromorpha3 at-

tached to the sides of the cephalothorax as well as to the

abdomen Oymnobates.

Tarsi of first pair of legs tapering at the tip; pteromorphc«

attached to the abdomen only 3.

3. Claws of the tarsi tridactyle 4,

ClaW' s of tarsi monodactyle Oribatodes.

4. Lamellte large, attached to the cephalothorax by their

posterior margins only Oribatella .

LamelUe moderate, attached to the cephalothorax by their

inner margins Oribata.

KEY TO THE GENERA OF NOTHRID^.

1. Mandibles rod-like, serrate Serrarius.

Mandibles chelate 2.

2. Last pair of legs distant from the others and saltato-

rial Zetorchestes.

Last pair not distant from the others, nor saltatorial, being

used for crawling 3.

3. Abdomen apparently divided into three parts by a pair of

oblique sutures passing backward from the posterior

edge of the cephalothorax to the middle of the lateral

margins of the abdomen Trizetes.

Abdomen without such oblique sutures 4.

4. Integument thin and little chitinized; variously colored . . 19.



Integument well chitinized; color brown 5.

5. Cephalothorax with lamellae 6.

Cepbalothorax without lamellaB 12.

6. Body smooth 7.

Body rough 8.

7. Last three pairs of legs situated under the body. . Liacarus.

Last three pairs of legs situated at the sides of the

body NoTASPis.

8. No demarcation between the cephalothorax and ab-

domen SCUTOVERTEX.
Cephalothorax and abdomen plainly divided 9.

9. Ungues monodactyle; femora I and II pedunculate 10.

Ungues tridactyle 11.

10. Lamellifi large, blade-like Tegeocranus.
Lamella^ merely low chitinous ridges Carabodes.

11. Femur I pedunculate Chaunoproctus.
Femur I not pedunculate Cepheus.

12. Legs slender, longer than body, segments pedunculate. . 13.

Legs short and stout 14.

13. Cephalothorax and abdomen coalescing at the median
plane Amerus.

Cephalothorax and abdomen plainly divided Dam^us.
14. Ungues monodactyle; dorsum of abdomen convex 15.

Ungues tridactyle 16.

15. Genital and anal covers separate; situated in the ventral

plate Hermannia.
Clenital and anal covers contiguous; no ventral plate pres-

ent LOHMANNIA.
16. Dorsum of abdomen convex 17.

Dorsum of abdomen flat or concave 18.

17. Abdomen with concentric rings on the dorsum; ventral

plate present Neoliodes.

Abdomen without concentric rings on the dorsum; ventral

plate absent Tumidalvus.
18. Body elliptical; leg II with tectopedia Cymb^erem^us.

Body rectangular; leg II without tectopedia Nothrus.



351

19. Abdomen without transverse suture. . . . Triiypochthonius.
Abdomen with transverse suture 20.

20. Ungues tridactyle, with inner dactyle less than half

as long as the others; cephalothorax truncate in.

front Parhypochthonius.
Ungues either monodactyle or tridactyle, if tridactyle,

dactyles of equal length; cepbalothorax not truncate in

front Hypochthonius.

KEY TO THE GENERA OF HOPLODERMID^E.

1. Genital and anal openings situated apart; ventral plate

large Mesoplophora.

Genital and anal openings situated together; ventral plate

small or rudimentary 2.

2. Ungues monodactyle; genital and anal covers sepa-

rate Hoploderma.

Ungues tridactyle; genital and anal covers coalescing.

Phthiracarus.

Descriptions of Species.

Thirty-three species from Illinois are described in the

following pages, and of this number twelve are new. In every

case the author has made figures illustrating the new species,

and a few figures have been made of some of our most common
American species. The species are arranged in the natu-

ral order under each genus, a key being given to aid in

their identification. The genera and families are similarly

arranged, the leading characters being given for each group.

Family ORIBATIDJ^:.

Forms with the cephalothorax and abdomen immovably

fused together; body not compressed; mouth-parts very small;

trachect' opening at the acetabula of the legs. Abdomen
possessing chitinous wing-like expansions called pteromorphie;

integument usually suiooth and shiny. Legs never with

swollen or moniliform segments.



352

Genus Oribatella Banks.

Ungues tridactyle; pteromorphiP attached to the abdomen
only; lamelhp large, attached to the cephalothorax by their

posterior margins.

Two species:

Pteromorphae truncate, not extending beyond the anterior mar-

gin of abdomen quadridenfafa.

PteromorphcB extending almost to the tip of the rostrum.

ovalis.

Orilndella qKadridentata Banks.

1895. Oribatella 4-dcntata, Banks, Trans. Amer. Ent. Soc, Vol. XXII., p. 9.

1898. Orihala quadridenfafa, Michael, Das Tier., Lief. 3, p. 19.

Dark brown; integument brittle; surface slightly rough.

Cephalothorax about as broad as long and almost entirely

hidden from above by the lamellae, which are very large, project-

ing beyond the rostrum and ending each in twosubequal cusps;

lamellae almost touching each other and twice as long as broad.

No translamella. Lamellar hairs almost straight, pectinate and

directed forward. There are two very much curved, pectinate

rostral hairs; also a pair of similar but straight interlamellar

hairs; pseudostigmatic organ large, clavate, and pectinate, about

two thirds as long as the lamellae. Just behind each pseudo-

stigma is a short, stout, pectinate bristle.

Abdomen almost as broad as long, pteromorphie truncate,

not extending beyond the anterior margin of the abdomen,
their anterior margin slightly concave. There is a whorl of

about a dozen stout, curved, pectinate bristles around the mar-
gin of the abdomen. Anal covers slightly larger than the

genital covers, and situated about their own length from the

posterior margin of the abdomen and twice their length from
the genital plates. Legs small and short.

Length, 0.56 mm.; breadth, 0.38 mm.
Under logs and boards. Collected by the writer at Urbana,

lib Many specimens. Mr. Banks has confirmed the determi-

nation of this species.



353

Or ibatella oralis C. L. Koch.

1835. Oribateg oralis, C. L. Koch, Crust. Myr. Arach., Heft 3, Tab. 5.

1877. Oribates oralis, Canestrini & Fanzago, Atti 1st. Venet., Ser. 5, Vol. IV.,

p. 82.

1855. Oribata nitem, Nicolet, Arch. Mus. Paris, T. VII., p. 433, PI. IV.,

Fig. 6.

1884. Oribata punctata, Michael, Brit. Orib., Vol. I., p. 253, PI. IX., Fig. 1-14.

1883. Oribates nicolef a, Berlese, Acari, Myr., Scorp., Fasc. III., Nr. 3.

1895. Oribatella armata, Banks, Trans. Amer. Ent. Soc, Vol. XXII., p. 9.

1898. Oribata omlis, Michael, Das Tier., Lief. 3, p. 19.

Dark walnut-brown; integument thick and very resistant;

surface pitted.

Cephalothorax short and almost entirely hidden by the

large lamellae. Lamellae greatly enlarged, as long as the ceph-

alothorax; pseudostigmata pyriform; pseudostigmatic organ

large, clavate, and about two thirds as long as the cephalo-

thorax.

Abdomen oblong. Pteromorphae very large, almost as long

as the entire body, and ending anteriorly in a long, sharp-

pointed process. Anal covers about half as long again as the

genital covers.

Legs rather small and hidden by the large pteromorphae.

The anterior pair project about half their length in front of the

apex of the rostrum; the posterior extend slightly beyond the

posterior margin of the abdomen. Tibia of the tlrst two pairs

rather short.

Length, 0.60 mm.; breadth, 0.42 mm.

In moss. Collected by C. A. Hart, from the pitcher-plant

{Sarracenia [jHrpntra), in bog, at Cedar Lake, 111., and by the

author at Homer, 111.

Genus Oribata Latreille.

Superior bristles not spatulate; mandibles stout; integu-

ment usually smooth; pteromorphit' attached to the a})domen

only; ungues tridactyle; lamella' attached by means of their

inner margins to the dorsal surface of the cephalothorax.



854

KEY TO SPECIES.

1. Pteronioi'phai rounded anteriorly and extending almost

to the tip of the rostrum 2.

Pteromorphye truncate in front and not extending beyond
the anterior margin of the abdom en 4.

2. Pteromorphiri^ smooth; antero-ventral margin deeply emar-
ginate emarginata.

Pteromorphte somewhat wrinkled; antero-ventral margin
irregularly rounded 3.

8. Abdomen unicolor; with four large, snbequal bristles situated

on the posterior margin rohuda.

Abdomen with eight dark spots on the dorsum; no bristles

on the posterior margin odoptmctatu.

4. With a translamella 5.

Without a translamella 10.

5. Pseud ostigmatic organ short, subcapitate 6.

Pseudostigmatic organ long, clavate or lanceolate 9.

6. Translamella short, very broad, being as broad as long.

spinof/enualfi.

Translamella very narrow, almost reduced to chitinous

ridges 7.

7. Translamella curved gradually backward from the ends to

the center unimaciilafa.

Translamella doubly curved, giving rise to a small median
cusp....... 8.

8. Lamellar hairs one and a half times as long as the la-

mellae turgida.

Lamellar hairs scarcely as long as the lamellae wlnuscula.

9. Femora of legs II with lateral blade-like expansions. /?/6^c/'/;^.s'.

Femora of legs II without lateral blade-like expan-

sions adilamellata.

10. Abdomen oblong, being much longer than broad 11.

Abdomen globose 13.

11. Pseudostigmatic organs slender, lanceolate, and clavate. 12.

Pseudostigmatic organs short, subcapitate (irhorea.



355

12. Lamella' large, broad, three fourths as long as the rephalo-
thorax rirf/itiicd.

Lamellae very small, short, about one fourth as long as the
cephalothorax /xfrn/oinc/Zata.

18. Abdomen hairless iHinoismais.

Abdomen with prominent hairs hanksL

Orihata cn/arf/utata Banks.

1895. Orihala onarginata, Banks, Trans. Amer. Ent. Soc, Vol. XXI 1., p. 7.

Dark brown; integument very hard; surface smooth.

Lamellae absent. Rostrum stout, with a rounded anterior

end; rostral hairs curved and pectinate; tectopedia blade-like

and two thirds as long as the rostrum; pseudostigmatic organ

clavate and pectinate, about as long as the tarsus of leg I;

interlamellar hairs stout and pectinate.

Abdomen slightly pyriforni and hairless; pteromorplue

slightly pointed, extending forward almost to the tip of the

rostrum; anal and genital openings far apart; genital covers

about two thirds as long as the anal covers. Females with a

long, segmented ovipositor, which is often extended when the

mite is killed in hot water. This ovipositor is trilobed distally,

each fork bearing two large bristles.

Legs subequal in length ; fourth pair longest; second pair with

very stout femora. First pair of legs twice as long as the ceph-

alothorax; tarsus the longest segment, bearing a large plumose

hair at a point about one third the distance from the proximal

to the distal end of the segment; tibia much shorter than the

tarsus and globose distally; genual as long as the tibia, but only

about half as broad; femur large; coxa small.

Length, 0.89 mm.; breadth, 0.50 mm.
Under logs and in rubbish. Collected by the writer at

Areola, (Jrbana, (lalesburg, Chicago, and Marshall. III. Mr.

Banks has conhrmed the determination of this species.

Orihdfa n>h,tst<i Banks. (PI. XXXIII., Fig. 4.)

1895. Orihata robui<l((, Banks, Trans. Amer. Ent. Soc, Vol. XXII., p. 7.

Uniform light brown; integument thin and brittle.



356

Cephalofchorax broader than lon^. The lamellye and trans-

lamella consist each of a narrow blade on edge; translamella

slightly narrower than the lamellae and continuous with them,

the whole being sublunate; lamellar hairs as long as the ceph-

alothorax, straight and pectinate; rostral hairs stout, curved,

and pectinate, a little longer than the pseudostigmatic organ.

Abdomen broader than long, with a few small hairs; ptero-

morphiB very long and prominent, projecting beyond the tip of

the rostrum, rounded in front and pointed behind. Anal covers

three fifths as broad as long, and situated one half their length

from the posterior margin of the abdomen; genital covers

about two thirds as long as the anal covers, similar to them in

form, and situated about twice their length from the same.

Legs subequal in length; hind pair slightly longest; tibia

and tarsus of leg I subequal, genual one half as long as the

tibia, femur a little longer than the genual. The femur of leg

II is very much enlarged, and is half as long again as the

femora of the two posterior legs.

Length, 0.88 mm.; breadth, 0.62 mm.
Collected by myself at Urbana, 111. Three specimens. Mr.

Banks has confirmed this determination from specimens sent

to him by the author.

Orihata octopundata, n. sp. (PI. XXXIV., Fig. 7.)

Light yellowish brow^n; integument thin,

Cephalothorax broad; pseudostigmatic organ very long, re-

curved, with a thin peduncle and a much enlarged, pectinate, sub-

cylindrical head; interlamellar hairs straight, pectinate, short,

and inclined toward the median plane, but projecting very little

forward; rostral hairs similar to the lamellar hairs but curved.

Abdomen broad, hairless, with a longitudinal row of four

small, oval dark spots on each side, the anterior spots

being much the largest; a few similar but very minute

spots on the dorsum also. Pteromorphas free, projecting

almost to the tip of the rostrum; both the anal and genital

covers situated about their length anterior to the anal covers.

Length, 0,54 ram.; breadth, 0.40 mm.



357

In moss. Collected by the writer at Homer, 111. Several
specimens,

Oribafa lipiuogenudld, n. sp. (PI. XXXIII., Fi^. 1.)

Dark reddish brown; integument thick and brittle.

Cephalothorax broad; lamellae horizontal and broad, being
broadest at the tips; lamella} with cusps; lamellar hairs as long
as the lamella? and pectinate; pseudostigmatic organ short,

with small peduncle and large clavate head; interlamellar hairs

long, pectinate, and straight; rostral hairs about as long as the
lamellar hairs and curved.

Abdomen two thirds as broad as long; pteromorphae
narrow, truncate, and lying close to the sides of the body;
genital covers two thirds as long as the anal covers and sit-

uated twice their own length in front of the latter. There is a
row of short, stout, almost straight hairs around the margin,
and about eight hairs on the summit of the dorsum.

Legs short and subequal.

Length, 0.60 mm.; breadth, 0.46 mm.
Collected by the writer at Areola, 111. Several specimens.

Oribafa unimacidata Banks.

1906. Galumna unimaculatn, Banks, Proc. Acad. Nat. Sci. Phila., Nov. 1906,

p. 490, PI. XVIII., Fig. 33.

Dark reddish brown; integument thick; surface smooth.

LamelUe large, about two thirds as long as the cephalo-

thorax, broader anteriorly than posteriorly; lamellar cusps

prominent, slightly bifid in front, the long, straight, pectinate

lamellar hairs extending from them; translamella about a third

as broad as the lamellae; anterior free edge concave. There are

two pairs of tectopedia, of which the inner pair isthe longer,

extending forward almost as far as do the tips of the lamellar

cusps, curved slightly toward the median plane, and bearing a

pair of long, curved, pectinate bristles. The outer pair of tec-

topedia are much thicker and shorter than the inner pair and

bear no bristles. Interlamellar hairs similar to lamellar hairs

but longer. Pseudostigmatic organs short and clavate, about

as long as the genual of leg I.



858

Abdomen subglobose, the dorsum bearing ten pairs of short,

stont, slightly curved pectinate bristles; two pairs are situated

just above the pteromorphae, two pairs on the crown of the dor-

sum, two pairs are posterior in position, and four pairs occur

around the margin of the abdomen. The pteromorphye are at-

tached to the anterior half of the side of the abdomen; are trun-

cate in front, and do not extend beyond the anterior margin of

the abdomen. Genital covers about three fourths as long as the

anal covers and situated one and a half times their length in

front of the latter.

Anterior pair of legs about two thirds as long as the body;

tarsus and tibia subequal; genual more than half as long as the

tibia. The tibia and genual of leg I each bear laterally a very

stout, slightly curved enlarged spine. Genual of leg II with a

similar spine. Ungues tridactyle.

Length, 0.80 mm.; breadth, 0.60 mm.
Under old boards. Collected by the writer at Areola, 111.

Several specimens. Mr. Banks has confirmed this determina-

tion from a specimen sent him by the author.

Oribata turglda Banks.

1906. Galumna furgida, Banks, Proc. Acad. Nat. Sci. Phila., 1906, p. 493.

Very light brown; integument smooth.

Cephalothorax short and wide; lamellae narrow, about

half as long as the cephalothorax, broader at the anterior

than at the posterior end; translamella equal to the lamellae in

width. Lamellar hairs long, straight and barbed, about one

and a third times as long as the lamellae; interlamellar hairs

slightly longer than the lamellar hairs; antero-lateral hairs

about two thirds as long as the lamellar hairs and curved as

usual. Pseudostigmatic organ short, subcapitate.

Abdomen about as broad as long, broadest near the middle,

hairless. Pteromorphae small, truncate anteriorly, and not ex-

tending beyond the anterior margin of the abdomen. Genital

covers slightly over half as long as the anal covers and situ-

ated about twice their length in front of the latter.



359

Anterior pair of legs about as long as the abdomen. Tarsus
and tibia of leg I siibequal; genual about a third as long as the
tibia; femur equal to tibia in length. At the distal end of tibia
of leg T. there is a small tubercle from which extends a long
tactile bristle, longer than the segment itself. Ungues tri-

dactyle; dactyles almost equal.

Length, 0.50 mm.: breadth, 0.42 mm.
Shaken from elm and from papaw by C. A. Hart at

Muncie, 111.

Orilmfii iii'nniscuhi Banks.

1907. (JaliuiDui mniuscuhi, Banks, Proc. Acad, Nat. Sci. Phila., Vol LN'III
p. 492, PI. XV., Fig. 11.

Dark reddish brown, legs paler; integument slightly rough,
heavily chitinized.

Cephalothorax about three fifths as long as the abdomen;
lamelhe large horizontal blades, anteriorly a fourth as broad as
long and at the posterior end a mere line; translamella a small
ridge. Lamellar hairs long, straight, and pectinate, about four
fifths as long as the cephalothorax. Pseudostigmata circular

and low, psendostigmatic organ short, with a very short

peduncle and a spherical head. Literlamellar hairs almost
exactly like the lamellar hairs. Rostral hairs much shorter

than these and slightly curved.

Abdomen as broad as long, hairless; pteromorphae one
fourth as broad as long, truncate anteriorly, extending back-

ward half the length of the abdomen and not projecting much
beyond the anterior margin; anal covers a third longer than

the genital covers and situated about half their length from the

posterior margin of the abdomen; genital covers situated about

twice their length in front of the anal covers.

Legs subequal in length; femora of the last two pairs much
enlarged, being tw^o thirds as broad as long, tibia and tarsus

subequal. At the distal end of the tibia on the first and the last

pair of legs is situated a tactile hair slightly longer than the

segment itself.

Length, 0.72 mm.; breadth, 0.52 mm.



8G0

Collected by myself at Urbana, 111. Many specimens. The
identification of this species has been confirmed by Mr.

Banks from a specimen sent him by the author.

Oribata fuscipes C. L. Koch.

1835. Zetes ephtppiatus, C. L. Koch, Crust. Myr. Arach., Heft 3, Tab. 7.

1884. Oribatafuscipes, Michael, Brit. Orib., Vol. I., p. 241, PL VII., Fig. 1, 2.

1895. Oribatella bklentata (?), Banks, Trans. Amer. Ent. Soc, Vol. XXII., p. 8.

1898. Oribata fuscipes, Michael, Das Tier., Lief. 3, p. 13.

Dark brown; integument thick and tough; surface almost

smooth.

Cephalothorax short; lamellae large, horizontal, twice as

long as broad, truncate in front and bearing there a straight

plumose hair as long as the lamellse themselves; translamella

a short blade; pseudostigmatic organ long, filiform, becoming

stouter apically, almost erect.

Abdomen two thirds as broad as long, with a row of long,

slightly curved bristles on the posterior margin and a few hairs

on the sides. PteromorphtB small, truncate in front. Anal

covers situated about two thirds their length from the posterior

margin of the abdomen; genital covers about two thirds as long

as anal covers.

Legs subequal; a small blade present on each of the fem-

ora of the first two pairs; the tarsus of leg I with a long bristle

near its proximal end; all the tarsi well clothed with hairs.

Length, 0.70 mm.; breadth, 0.44 mm.
Under boards and in moss. Collected by the writer at

Areola, 111. Four specimens. A specimen of this species was
sent to Michael, and he also identified it as 0. fuscipes.

Oribata artilamellata, n. sp. (PI. XXXIII., Fig. 2.)

Dark olive; integument of medium thickness, not very re-

sistant, finely pitted.

Cephalothorax about a third as long as abdomen; lamellae

narrow blades on edge, of uniform width, with small cusps;

translamella a narrow blade, about half as broad as the lamellae;

pseudostigmata cylindrical, longer than broad; pseudostigmatic



:501

organ clavate and pectinate, recurved, and of medium length;
interlamellar hairs subequal to lamellar hairs; rostral hairs
much smaller than these and very slightly curved.

Abdomen large, almost spherical, hairless; pteromorphie
rudimentary; anal covers about twice as long as genital covers;
genital covers situated about three times their length in front
of anal covers.

Legs subequal; femur of leg I extending to tip of rostrum,
tibia and tarsus subequal, genual a little less than half as long
as the tibia.

Length, 0.70 mm.; breadth, 0.46 mm.
Collected by the author at Areola, 111. Several specimens.

On'bata arborea Banks.

1895. Orihata arborea, Banks, Trans. Amer. Ent. Soc, Vol. XXII., p. 7.

Light chestnut-brown; integument smooth.

Cephalothorax half as long as the abdomen, triangular; la-

mellge long narrow blades, of about uniform width and about
two thirds as long as the cephalothorax; lamellar hairs straight

and apparently without barbs, about as long as the lamellae;

interlamellar hairs similar to lamellar hairs; antero-lateral

hairs but slightly curved and about three fourths as long as the

lamellar hairs. Pseudostigmata cup-shaped, slightly projecting;

pseudostigmatic organ clavate, recurved, and very slightly

barbed at the end.

Abdomen two thirds as broad as long, hairless; pteromor-

phae truncate anteriorly and not extending beyond the ante-

rior margin of the abdomen; anterior margin slightly emar-

ginate above; genital covers almost as long as the anal covers

but much narrow^er, situated about one and a half times their

length in front of the latter.

Anterior pair of legs two thirds as long as the abdomen.

Tarsus and tibia of leg I subequal; genual one half as long as

the tibia. From a small tubercle on the distal end of the

tibia of leg I extends a long tactile bristle, longer than the

segment itself. Ungues tridactyle; dactyles unequal.

Length, 0.45 mm.; breadtli, 0.80 mm.



362

Under bark. Collected by J. Douglas Hood at Muncie, 111.

One specimen.

Orihata virginiea Banks. (PI. XXXIV., Fig. 5.)

1906. Galumna rlrginkn, Banks, Proc. Acad. Nat. Sci. Phila., Nov., 1906, p.

493. PI. XVI.. Fig. 18 and 20.

Walnut-brown; integument brittle; surface rough.

Cephalothorax about a third as long as the abdomen; la-

mellse broad, blade-like, almost as long as the cephalo-

thorax, broadest at the middle, each with blunt apex bearing

the lamellar hair; lamellar hair straight, simple, about two

thirds as long as the cephalothorax; pseudostigraata large,

funnel-shaped; pseudostigmatic organ serrate, with long, thin,

recurved peduncle and clavate head; interlamellar hairs long,

thin, and pectinate; rostral hairs subequal to lamellar hairs and

slightly curved; three pairs of tectopedia, the first pair blade-

like and very narrow, the second and third pairs rounded.

Abdomen two thirds as broad as long, hairless; pteromor-

phse very narrow, truncate in front, and extending about two

thirds the length of the abdomen; anal covers triangular, fully

twice as long as the genital covers; genital covers rectangular,

small, and situated about twice their length in front of the anal

covers.

Legs subequal, the anterior pair extending in front of the

rostrum by about half their length.

Length, 0.50 mm.; breadth, 0.34 mm.
Under boards, bark, and logs, and in moss. Collected by

the wTiter at Homer, 111. Several specimens.

Oribata lontja, n. sp. (PI. XXXIV., Fig. 6.)

Light yellowish brown; integument rather thin; surface

rough.

Cephalothorax short; lamellae mere ridges; lamellar hairs

rather short, pectinate, and slightly curved; pseudostigmata

cup-shaped; pseudostigmatic organ long, recurved, lanceolate,

and strongly serrate on the antei:ior edge only, the posterior



868

edge being smooth; interlamellar hairs short and pectinate, in-

clined away from the median plane; rostral hairs small and

curved.

Abdomen twice as long as broad, hairless, dorsum ir-

regularly covered with small denticles; pteromorpha^ very long

and narrow, truncate in front; anal covers very much enlarged,

being twice as long as the genital covers; genital covers narrow

and situated about twice their length in front of the anal covers.

Legs small, first pair projecting about one third their length

beyond the rostrum.

Length, 0.54 mm.; breadth, 0.28 mm.
Tu moss. Collected ])y the writer at Homer, III. One

specimen.

On'hata illlnoisemh, n. sp. (PI. XXXIIL, Fig. 8.)

Olive brown; integument rather thick and tough, not very

resistant, somewhat rough.

Cephalothorax about a fourth as long as abdomen; lamellae

broad horizontal blades about three fifths as long as the ceph-

alothorax, broadest towards the middle, and with small cusps;

lamellar hairs simple, straight, as long as the cephalothorax

;

three pairs of tectopedia, the first pair blade-like, the second

large, rounded, and ending anteriorly in a long, sharp point,

the third rounded; pseudostigmatic organ short and stout, with

short peduncle and large, pectinate, clavate head; interlamellar

hairs straight, pectinate, and about two thirds as long as the

lamellar hairs; rostral hairs stout, curved, and pectinate.

Abdomen slightly longer than broad, hairless; pteromorpha?

prominent, truncate in front, with concave anterior margin,

and extending backward about two thirds the length of the ab-

domen; anal and genital covers subequal; anal covers situated

about half their length from the posterior margin of abdomen;

genital covers about one and a half times their length in front

of the anal covers.

Legs small, with several stout plumose bristles; the two

anterior pairs subequal, the first pair projecting half their

length in front of the rostrum.



364

Length, 0.48 mm.; breadth, 0.34 mm.
Collected by the writer at Areola, 111. One specimen.

Orihata banksi, n. sp. (Fig. 2 and 3, pp. 339, 340.)

Dark chestnut-brown, integument heavily chitinized; sur-

face pitted.

Cephalothorax about a third as long as the abdomen; la-

mellae blade-like, about half as long as cephalothorax, broadest

at the anterior end, without cusps; lamellar hairs straight,

pectinate, and about as long as the cephalothorax; first pair of

tectopedia very similar to lamellae; second pair round, cup-like.

Pseudostigmata cylindrical, distal end cup-shaped; pseudo

stigmatic organ slightly recurved.

Abdomen two thirds as broad as long, the dorsum with

four rows of long, curved, pectinate bristles, about five in each

row; pteromorphge large, truncate in front, not extending in

front of the anterior margin of abdomen, but extending back-

ward about half the length of the abdomen; anal and genital

covers rectangular, the anal ones a third longer than the

genital ones.

Legs stout; anterior pair about as long as the abdomen;

third pair smallest; femur of leg I about two thirds as long as

the cephalothorax.

Length, 0.54 mm.; breadth, 0.40 mm.
Under bark of dead trees and under rubbish of various

kinds. Collected by the author at Galton, Areola, and Homer,

111., and by C. A. Hart from pitcher-plants {Sarracenia purpurea)

in bog at Cedar Lake, 111. Several specimens.

Family NOTHRID^.

Cephalothorax and abdomen immovably fused or coalesc-

ing; body never compressed; tracheae opening at the acetabula

of the legs; abdomen without wings; integum*ent frequently

rough, sculptured, or reticulate, and sometimes very little

chitinized; legs frequently very stout, sometimes long and

moniliform.



865

Genus Liacarus Michael.

Mandibles chelate; le^s I and II approximate, as also legs

III and IV; lamell-ct present; body smooth; last three pairs of

legs inserted under the body.

KEY TO SPECIES.

1. Abdomen almond-shaped lucidus.

Abdomen oval 2.

2. Color brown ; integument thin and delicate minutus.

Color black ; integument thick and resistant B.

3. Translamella with a central cusp nirjer.

Translamella without a central cusp n if idus.

Liacarus lucidus, n. sp. (PI. XXXIV., Fig. 9.)

Light pea-green; integument thin and brittle; surface

smooth.

Cephalothorax long. Lamellae two thirds as long as ceph-

alothorax. They are blades on edge, of almost uniform width,

and without cusps; lamellar hairs about as long as lamelhu,

curved and pectinate; translamella similar to lamelke but only

about half as broad. Pseudostigmata funnel-shaped; pseudo-

stigmatic organ stout, short, pectinate, clavate, and slightly rcj-

curved; interlamellar hairs subequal to lamellar hairs but in-

clined away from the median plane; palpi prominent.

Abdomen almond-shaped, dorsum with four rows of short,

curved bristles, of which there are about six in each of the

outer rows and four in each of the inner ones.

Legs short, subequal; femora slightly enlarged.

Length, 0.48 mm.; breadth, 0.28 mm.
Collected by the writer at Areola, 111. Several specimens.

Liacarus minufus, n. sp. (PI. XXXV., Fig. 10.)

Brown; integument thin and delicate.

Cephalothorax rathei- short; lamelke narrow, being mere

blades on edge, two thirds as long as the cephalothorax, and

each }»earing a long, straight, pectinate lamellar hair, as long

as the lamella- themselves. Rostrum broad but somewhat



366

pointed at the apex; rostral hairs long, pectinate, curved slightly

toward the median plane. Palpi large, with four segments;

proximal and distal segments each with a curved bristle; pseu-

dostigmata small; pseudostigmatic organ as long as the femur

of leg 1, narrow at the base, clavate, pointed apically. Inter-

lamellar hairs twice as long as the pseudostigmatic organ.

Abdomen almost as broad as long. The progaster curves

convexly down to meet the cephalothorax. There are a few

short hairs present on the abdomen. Ventral plate large; anal

covers approximate to the dorsal margin of the abdomen, and

more than twice as large as the genital covers; genital covers

situated three times their length in front of the anal covers.

Legs subequal in length; femur and tarsus of the first pair

subequal, genual half as long as the tibia. No long bristles on

the first pair of legs; tibia of leg III wath a bristle as long as

the segment itself.

Length, 0.50 mm.; breadth, 0.32 mm.
Collected by the writer at Urbana, 111. A single specimen.

L'uicanm nhjer, n. sp. (PL XXXV., Fig. 11.)

Black; integument thick and very resistant.

Cephalothorax about half as long as the abdomen. Lam-
ellar hairs long, straight, and pectinate, projecting beyond

the tip of the rostrum. Rostral hairs curved, stout, and pecti-

nate. Pseudostigmatic organ long, clavate, and pectinate. The
lamellae are horizontal blades, bifid in front.

Abdomen oblong, with a few small hairs. Legs of moder-

ate length, the anterior pair projecting beyond the tip of

the rostrum by one third its length.

Length, 1.00 mm.; breadth, 0.64 ram.

In moss. Collected by the writer at Homer, 111. Two
specimens.

Liaairus nitUIus Banks.

1895. Cepheua nitiduii, Banks, Trans. Amer. Ent. Soc, Vol. XXII., p. 10.

Very dark brown; integument stout, smooth.



367

Cephalotliorax pyramidal. Lanielki' l)lade-like. l)road, ex-

tending almost the entire length of the cephalothorax and
united at their anterior ends by a very short but broad trans-

lamella; with small cusps. Lamellar hairs small, straight,

about three hfths as long as the lamelhe; interlamellar hairs

similar to the lamellar ones but slightly larger; antero-lateral

hairs about as long as the lamellar ones and almost straight.

Pseudostigmatic organ fusiform, about two thirds as long as

the lamella^.

Abdomen subglobose; hairless. Genital covers much smal-

ler than the anal covers; anal covers slightly broader posteriorly

than anteriorly, and situated one third their length from the

posterior margin of the ventral plate.

Anterior pair of legs about as long as the abdomen. Tarsus

and tibia of leg T subequal; genual about three fifths as long as

the tibia; femur almost twice as long as the genual. Tactile

bristle of tibia I about as long as the segment itself. Claws

with three equal dactyles, and situated on small tarsal pedicels.

Length, 0.88 mm.; breadth, 0.72 mm.
Collected liy the writer at Areola, 111.

Genus Notaspis Hermann.

Integument well chitinized; cephalothorax with lamelhe;

body smooth; last three pairs of legs situated laterally.

KEY TO SPEOIES.

1. Abdomen without hairs pf/ro.sfifjtiKffd.

Abdomen with hairs 2.

2. Outer margins of lamella' slightly emarginate near middle;

length of body not over 0.60 mm ^ip/tt i/x's.

Outer margins of lamelhi^ straight; length of body about

0.90 mm hipi/is.

Xotasp/s ptjr(»sti(jniuf(i, n. sp. (PI. XXXV., Fig. 12.)

Very light yellowish brown; surface of integument rough.

Cephalothorax long; lamellie narrow ])lades, broadest at

the anterior ends; hiniellar hairs about half as long as the



868

cephalothorax, slightly curved, pectinate; translamella a

straight cross-bar; pseudostigmata cup-shaped; pseudostig-

matic organ with a small short peduncle and a large pyriform

head; interlamellar hairs of medium length, straight, and
pectinate.

Abdomen almond-shaped, hairless; anal covers contiguous

to the posterior margin of the abdomen; genital covers two
thirds as long as the anal covers, and situated about three

times their length in front of them.

Hind pair of legs longest, but not reaching to the posterior

margin of the abdomen; the other pairs subequal.

Length, 0.42 mm.; breadth, 0.20 mm.
Collected by the writer at Areola, 111. Many specimens.

Notaspis spinipes Banks.

1906. Oppia spinipes, Banks, Proc. Acad. Nat. Sci. Phila., Nov., 1906, p. 496,

PI. XVIL, Fig. 22.

Chestnut brown; surface of integument smooth.
Cephalothorax very long and narrow, almost as long as the

abdomen; lamellae very long, narrow, their blades extending
the entire length of the cephalothorax; lamellar cusps prom-
inent, pectinate, straight, and short; pseudostigmatic organ
long, straight, and pectinate; interlamellar hairs straight, pec-

tinate, pointing almost directly forward; rostral hairs small,

simple, and curved.

Abdomen circular, with two pairs of large, straight, pec-

tinate spines on the dorsal margin; anal covers about the same
size as the genital covers and contiguous to the posterior mar-
gin of the abdomen.

Legs subequal, with several stout, curved, plumose bristles;

tactile hairs on the tibiae of the first two pairs about twice as

long as the segments themselves.

Length, 0.56 mm.; breadth, 0.34 mm.
In moss. The author has collected specimens at Areola,

111. The determination has been confirmed by the original

describer of the species.



369

Xofaspls b/'jti/ls Ileriii.

1804. Xotas})ls bipilis, Hermann, Mem. Apt., p. 95.

1841. Murcia acuminata, C. L. Koch, Crust. Myr. Aracli., Ileft 31, Tab. L'4

(Nymph).

1844. Oppia cornxfa, C. L. Koch, Crust. Myr. Arach., Heft 08, Tab. 8.

1855. Notaspis bipilis, Nicolet, Arch. Mus. Paris, Vol. VIL, p. 448, PI. III., Kig.6.

1883. Xotaspis bipilis, Berlese, Bull. Soc. Ent. Ital., Vol. XV., p. 211t.

1885. Oppia bipilis, Berlese, Acari, Myr., Scorp., Fasc. XX., Nr. 8.

1888. Notaspis bipilis, Michael, Brit. Orib.,Vol. II., p. 356, PI. XXVII., Fig. 1-9.

1898. Notaspis bijiilis, Michael, Das Tier., Lief. 3, p. 46.

Chestnut brown; integument smooth.

Cephalothorax large, one half as long as the entire body.

Lamella) veiT long and slender, almost as long as the entire l)ody

and of almost the same width throughout; anterior two hfths of

lamelhe free. There is only a slight indication of a trans-

lamella. Lamellar hairs straight, pectinate, about half as long as

the lamella?; interlamellar hairs very large, as long as the entire

cephalothorax, pectinate, and situated at the posterior margin
of the latter; antero-lateral hairs straight, similar to lamellar

hairs but smaller. Pseudostigmata but slightly projecting,

funnel-shaped; pseudostigmatic organ long, hliform, pectinate.

Abdomen globose, bearing on its postero-dorsal aspect two

pairs of large, straight bristles, and on its postero-ventral

aspect a transverse row of four subequal straight ones, about

half as long as the dorsal bristles. Genital covers semicir-

cular, situated slightly more than their length from the anal

covers; anal covers much larger than the genital covers, and

situated a))out a third their length from the posterior margin

of the ventral plate.

Anterior pair of legs about as long as the entire body;

tarsus one and a half times as long as the tibia; tactile

bristle of tibia straight, as long as the tarsus. Claws of tarsi

with three unequal dactyles.

Length, 0.90 mm.; breadth, 0.6S mm.
In moss. Collected by L. M. Smith at Parker, ill., and by

the writer at Areola, 111. My determination of this species has

been confirmed by a comparison of my specimens with a

mounted one of hipili^ sent me by Michael,



370

Genus Ttf/cuvranus Nicolet.

Body rough; cepbalothorax and abdomen plainly divided;

ungues monodactyle; lamellae large, blade-like.

Two species:

Integument granular velatus.

Integument reticulate lamellatus.

Tegeocranus vdatda Michael.

1880. Tegeocranus velatus, Michael, Jour. JRoy. Micr. Soc, Vol. III., p. 189,

PI. VI., Fig. 6-9.

1884. Tegeocranus velatm, Michael, Brit. Orib., Vol. I., p. 313, PI. XXXI.,
Fig. 9-15.

1895. Tectocepheus relatus, Berlese, Acari, Myr., Scorp., Fasc. LXXVII., Nr. 2.

1898. Tegeocranus velaf us, Michael, Das Tier., Lief. 3, p. 35.

Light brown; integument coarsely granular.

Cepbalothorax trapezoidal. Lamellae almost as long as the

cepbalothorax, the anterior lamella one third free;translamella

reduced almost to a line. Lamellar hairs short, stout, and

pectinate on their outer borders only, peculiar in that they are

so greatly curved inward that their tips may touch; interlamel-

lar hairs wanting. Pseudostigmata cup-shaped, slightly pro-

jecting; pseudostigmatic organ subcapitate, with a long pec-

tinate head.

Abdomen almost as broad as long and peculiar in possess-

ing a lateral, chitinous, shelf-like expansion at the shoulders,

which extends backward along the lateral margin to about the

middle of the abdomen, and is transversely wrinkled. Genital

covers much smaller than the anal covers, and situated about

their length from the latter; anal covers situated about a third

their length from the posterior margin of the abdomen.

Legs rather short, subequal, about three fourths as longXs
the abdomen, sparsely clothed with rather short, stout hairs.

Tibia slightly longer than the tarsus; claw of tarsus stout, two
thirds as long as the segment itself.

Length, 0.38 mm.; breadth, 0.30 mm.
In moss. Collected by the writer at Muncie, 111.



371

Tec/eocranus lamellatus Banks.

1906. Cepheus lamellatm, Banks, Proc. Acad. Nat. Sci. Phila., 1006, p. 497.

Very dark brown, almost black; integument strengthened
with an irregular network of chitinous ridges.

Cephalothorax short, broad. Lamellte very large, each
about half as broad as the cephalothorax and extending almost
the entire length of the latter; lamella? united in front by a

very short, broad translamella. Lamellar hairs stout, curved

strongly inward, about two thirds as long as the lamellae; inter-

lamellar hairs very short, almost straight, and approximate to

the lamelk^. Pseudostigmata cup-shaped, projecting; pseudo-

stigmatic organ consisting of a stout, straight pedicel with a

small, oblong, pectinate head.

Abdomen almost as broad as long, semicircularly rounded

behind. Dorsum with rather stout shoulder bristles and with

several other bristles at the posterior end. Genital covers

slightly smaller than the anal covers, and situated about half

their length from the latter; anal covers situated their length

from the posterior margin of the aJjdomen.

Anterior pair of legs three fourths as long as the abdomen.

Tarsus of leg I one and a half times as long as the tibia. Tarsal

claws stout, sharp, and strongly curved. Legs sparsely clothed

with long straight bristles.

Length, 0.76 mm.; breadth, 0.66 mm.
In moss. Collected by the writer at Areola, 111. One

specimen.

Genus DAMiEus C. L. Koch.

Mandibles chelate; legs slender, much longer than the

body, I and II approximate, as also III and IV; legs IV crawl-

ing organs; lamelke absent; cephalothorax and abdomen

clearly demarcated from each other.

Two species:

Pseudostigmatic organ simple, not pectinate sirfflexus.

Pseudostigmatic organ pectinate n ifens.



372

Daiuwns sufflexns Michael.

1885. Dam.ruK suffie.rus, Michael, Jour. Roy. Micr. Soc, Ser. 2, Vol. V., p. 394,

PI. VII., Fig. "9.

1888. Damivm sufflexus, Michael, Brit. Orib., Vol. II., p. 415, PI. XXXIV.,
Fig. 9, 10.

1895. Belha svfflexa, Berlese, Acari, Myr., Scorp., Fasc. LXXIV., Nr. 4.

1898. Damxus sufflexus, Michael, Daa Tier., Lief. 3, p. 58.

Light brown, legs almost yellow; integument of cephalo-

thorax rather rough, abdomen smooth.

Cephalothorax subrectangular, pointed at apex, with a

rather large boss under each pseudostigma. Lamellar hairs

absent; rostral hairs stout, slightly curved. Pseudostigmata

long, nearly upright, cylindrical
;
pseudostigmatic organ filiform,

very long, about equal in length to the cephalothorax.

Abdomen globular; progaster rounded; notogaster with a

row of about five short, stout, slightly curved hairs on each

side, which project slightly beyond the side of the abdomen.

Ventral plate small; anal and genital covers of almost exactly

the same size and form, with a very narrow margin between

them.

Legs rather long, of medium thickness, and typical of the

genus. Femur of leg I twice as long as the genual, and with

two large bristles on the outer distal margin; genual two thirds

the length of the tibia; tibia two thirds the length of the tarsus;

tarsus globose proximally and tapering distally, with a very

stout bristle on the outer proximal margin.

Length, 0.70 mm.; breadth, 0.42 mm.
Under logs. Collected by the writer at Urbana, 111.

Dammus nitens C. L. Koch. (Fig. 1, p. 339.)

1834. Oppia nltem, 0. L. Koch, Crust. Myr. Arach., Heft 3, Tab. 10.

1888. Damxus nitens, Michael, Brit. Orib., Vol. II., p. 409, PI. XXXIV.,
Fig. 1-8.

1895. Belba minufa, Banks, Trans. Amer. Ent. Soc, Vol. XXII., p. 12.

1898. Damrcus nitens, Michael, Das Tier., Lief. 3, p. 57.

Light yellowish brown; integument polished.

Rostrum broad, about a third the length of the cephalo-

thorax; translamella absent; pseudostigmata very small; pseu-



373

dostigmatic organ slender, pectinate, and clavate. The general

shape of the cephalothorax is that of an isosceles triangle with

its base corresponding to that of the cephalothorax.

Abdomen oval, with about twelve short, slightl}' curved

bristles; progaster curved down convexly to meet the cephalo-

thorax. Ventral x^late large; anal covers large, almost attain-

ing the posterior margin of the abdomen, and about twice

their length from the genital covers, which are al)Out three

fourths as long as the anal covers and situated very near the

anterior margin of the ventral plate.

First pair of legs almost as long as the body, and each

succeeding pair slightly longer than the preceding one. Tarsus

of the first pair of legs somewhat globose at the distal end;

00X36 of the third pair globular, each bearing a large bristle

on its anterior end; tibia? of fourth pair each bearing on the

anterior distal margin a large bristle as long as the tibia itself.

Length, 0.50 mm.; breadth, 0.28 mm.
Collected by the writer at Urbana, 111. Many specimens.

I find that my examples of this species agree with a European

specimen of nitens sent to me by Mr. Michael.

Genus Hermannia Nicolet.

Without lamellae; legs short and stout; ungues monodactyle;

dorsum of abdomen convex; genital and anal covers separate

and placed in a ventral plate.

One species

—

histr lata.

Hermannia hisfriata Nicolet.

1840. Nothrus palliatus, C. L. Koch, Crust. Myr. Arach., Heft 30, Tab. 4

(Nymph).

1880. Herinannia bistriatu, Michael, Jour. Roy. Micr. Soc, Vol. III., p. 42.

1885. Nothrus bistriatas, Berlese, Acari, Myr., Scorp., Fasc. XVII., Nr. 9.

1888. Hermannia bistriatu, Michael, Brit. Orib., Vol. II., p. 462, Pi. XLII.,

Fig. 8-14.

1898. Hermannia bistriata, Michael, Das Tier., Lief. 3, p. 63.

Dark chestnut-brown; integument rough, and in some

places slightly pitted.

Cephalothorax fully half as long as the abdomen, w^ith two

chitinous ridges on the dorsal surface, which, beginning at the



374

rostrum, pass backward almost parallel to each other for about

one half the length of the cephalothorax, then diverge,

passing to the outer border of the pseudostigmata, with which

they fuse, and from the posterior border of which they turn

transversely toward the median plane, where they meet.

There is a single pair of stout hairs on the dorsal surface at

the base of the rostrum, which are curved towards the median
plane. Pseudostigma a circular chitinous ridge; pseudostig-

matic organ straight, slightly clavate, and directed anteriorly.

Abdomen subrectangular, two thirds as broad as long, sides

convex, posterior end rounded. An irregular chitinous ridge

lies on each side near the median plane; about midway between

this ridge and the lateral margin of the abdomen is situated on

each side a more regular chitinous ridge which curves similarly

toward the lateral margin. There are several short, curved

bristles on the lateral margins, two rows parallel to the median

plane, and six rather prominent pairs near the posterior mar-

gin, all of which curve inward. Ventral plate triangular,

genital and anal covers together extending almost its entire

length.

Anterior pair of legs about as long as the abdomen.

Tarsus of leg I longer than the tibia but not so stout; claw

of tarsus almost half as long as the segment itself. All the

segments of the legs except the tarsus possess stout, curved

bristles. The bristles of the tarsus are slender and more
numerous than those of the other segments.

Length, 0.85 mm.; breadth, 0.48 mm.
Under logs and in moss. Collected by J. Douglas Hood at

Urbana, 111., and by the writer at Areola, 111.

Genus Hypochthonius C. L. Koch.

Mandibles chelate; last pair of legs not distant from the

others; integument thin, little chitinized, variously colored;

abdomen with a transverse suture; cephalothorax not truncate

in front.

One species,—rw/w^ws.



375

Ihjpoclithou'nix riifnJus C. L. Koch.

1835. Hypochtho)tim rufulufi,C. L. Koch, Crust. Myr. Arach., Heft 3, Tab. 19.

1855. Leisoma omia, Nicolet, Arch. Mus. Paris, I. VII., p. 395, PI. II., Fig. 5

(Nymph).

1888. 'irt/pochthmilnxritfahi.'^, Michael, Brit. Orib., Vol. II., p. 534, PI. XLIX.,
Fig. 6-13.

1898. Ifi/pochtJioiiius rufuhts, Michael, Das Tier., Lief. 3, p. 77.

Body reddish; legs brown.

Cephalothorax very long.two thirds as long as the abdomen.
Pseudostigmata short, cylindrical; pseudostigmatic organ long

and recurved, with a row of long teeth on the anterior side; a

pair of long bristles, almost as long as the pseudostigmatic or-

gan itself, in front of the pseudostigmata; palpi very prominent
Abdomen broad, divided by a transverse suture into two

equal parts; flattened at the sides, forming blades which extend

almost the entire length of the abdomen; many large bristles.

Legs short, stout, and subequal; segments cylindrical.

Length, 0.66 mm.; breadth, 0.40 mm.
Collected by the writer at Areola, 111. Two specimens.

Family HOPLODERMIDtE.

Cephalothorax hinged to the abdomen and capable of

being folded down upon its ventral surface so as completely

to hide the legs and mouth-parts; body generally compressed;

no trachete present; month-parts large, mandibles powerful;

legs stout, never with swollen or moniliform segments;

cephalothorax frequently with a median carina.

Genus Hoploderma Michael.

Genital and anal openings situated together but with their

covers separate; ventral plate small or rudimentary; ungues

monodactyle.

Two species:

Total length of body not over 0.60 mm spluerula.

Total length of body over LOO mm dasi/jjus.



376

Hoploderma si^hwrula Banks.

1895. Hoploderma splumda, Banks, Trang. Amer. Ent. Soc, Vol. XXII., p. 16.

Dark brown; integnment smooth.

Cephalothorax one half as long as high; dorsal surface

with two pairs of bristles,—a very long, almost straight pair,

three fourths as long as the cephalothorax itself, situated near

the posterior border, and a small, curved pair near the tip.

Pseudostigmata round, situated at the postero-lateral extrem-

ity of the cephalothorax; pseudostigmatic organ slightly re-

curved.

Abdomen subglobose; upper half of the anterior margin

concave, lower half straight ; ventral margin moderately

convex; dorsum with two rows of submedian bristles, six bris-

tles in each row. Genito-anal covers almost completely con-

cealed when viewed from the side, the anterior corner, however,

visible as a triangular chitinous projection.

Anterior pair of legs stouter than the other pairs, which

are subequaJ. Tarsus of leg I nearly twice as long as the

tibia; tibia slightly longer than the genual; femur longer than

the tibia and genual combined. Claws slightly more than

half as long as the tarsi from which they extend. All the legs

are sparsely clothed with rather long, simple bristles.

Length, 0.55 mm.; height, 0.40 mm.
Under a log. Collected by the writer at Mahomet, 111.

Hojiloderma dasypns Ant. Duges.

1834. Oribata dasypus, Ant. Duges, Ann. Sci. Nat., Ser. 2, T. II., p. 47.

1841. Hoplophoralentula, C. L. Koch, Crust. Myr. Arach., Heft 32, Tab. 16.

1841. Phthlracarus contractilis, Perty, Allg. Naturg., Bd. III., p. 874.

1868. Hoplopliora contractilis, Claparede, Zeit. Wiss. Zool., Bd. XVIII., p. 507.

1877. Hoplopliora contractilis, Murray, Econ. Ent., Apt., p. 222.

1883. Hoplop)hora dasypus, Berlese, Acari, Myr., Scorp., Fasc. VI., Nr. 4.

1885. Hoplophora dasypus, Canestrini, Prosp. Acar. Ital., Pt. I., p. 46.

1887. Tritia lentula, Berlese, Acari, Myr., Scorp., Fasc. XXXVI., Nr. 3.

1888. Hoplophora dasypus, Michael, Brit. Orib., Vol. II., p. 560, PI. L.,

Fig. 8-14.

1898. Hoploderma dasypus, Michael, Das Tier., Lief. 3, p. 79.

Pale drab; integument thick and tough but not brittle.

Cephalothorax a fourth as long as abdomen, with a single



377

pair of small hairs; pseudostigmatic organ small, scarcely visible,

clavate, and simple. Palpi and labial organs prominent.

Abdomen almost as broad as long, rounded behind, with

three rows of long bristles on each side of the dorsum, the inner

row having the largest bristles; three bristles in each of the

outer row^s.

Legs subequal, with many long hairs.

Length, 0.84 mm.; height, 0.56 mm.
In decayed wood. Collected by myself at Areola, 111. A

specimen of this species was sent to Michael to get his confir-

mation of the identification. He writes that my specimen

agrees with (Ja.^i/pi(s except that it has no hairs on the abdomen.

These hairs had evidently been broken off, as they are present

on the other specimens which I have.

Genus Phthiracarus Perty.

The characters are the same as for the genus lloploilcnud

except that the genital and anal covers coalesce and the tarsal

claws are tridactyle.

Two species:

Cephalothorax hairless JlafjrlliJ'onnls.

Cephalothorax with six long hairs amerkanus.

PJdhiraeanis ^fiauelllformis, n. sp. (PL XXXV., Fig. 13.)

Dark olive-brown; integument thick but not brittle; surface

rough.

Cephalothorax about a third as long as the abdomen,

hairless; pseudostigmata round and flat, with radiating furrows;

pseudostigmatic organ Hagelliform and of moderate length;

labial organs and palpi prominent.

Abdomen two thirds as broad as long, pointed at the pos-

terior end, and with a few fine hairs. Legs subequal, clothed

with many hairs.

Length, 0.72 mm.; height, 0.40 mm.

Under logs. Collected by myself at Homer, 111. A few

specimens.



378

Phthiracarus americanus, n. sp. (PI. XXV., Fig. 14.)

Pale pinkish brown; integument well chitinized and

covered with small pits.

Cephalothorax twice as long as broad; mandibles very

stout and prominent, capable of retraction until invisible;

pseudostigmatic organ clavate, of medium length. From each

pseudostigma a ridge runs forward along the side of the aspis

to its lateral edge. A pair of hairs about two thirds as long as

the cephalothorax is situated at its posterior margin, and in

front of this pair is a similar one, the hairs about two thirds

as long; rostral hairs about two thirds as long as this last pair.

Abdomen about three fifths as broad as long and very

narrow, pointed behind, truncate in front, covered with small

pits. The dorsum has four rows of long, slightly curved

bristles, about five in each row; and there are four pairs of

short, straight bristles on the posterior ventral surface.

Legs subequal, as long as cephalothorax; claws tridactyle,

and half as long as the tarsi; tarsus twice as long as the tibia,

and with many long hairs. The tarsus of leg I bears a long

tactile bristle half as long again as the tarsus itself; tibia and

genual subequal.

This species differs from Phthiracarus arduus in that the

pseudostigmatic organ is much shorter and clavate, while on

the side of the aspis there is only one ridge instead of two.

Length, 0.70 mm.; height, 0.36 mm.
Under logs and boards. Collected by the writer at Dan-

ville, Areola, and Urbana, 111. Many specimens.



879

A List of the Known North American
Species of Oribatoidea.

In the following list the same natural order is ohserved

with respect to the families and genera as is used in the pre-

ceding keys and descriptions, but the species are arranged
alphabetically. The single citation for genus or species is to

the original description. All the known habitats and localities

are given.

Family OKIBATID^.

Genus Pelops C. L. Koch.

Pelopx C. L. Koch. Crust. Myr. Arach., Heft 2, 1835.

P. awericainis Ewing. Psyche, Vol. XIV., j). 111.

In moss, Batavia, 111.

Genus Gymnobates Banks.

aymnobates Banks. Can. Ent., Vol. XXXIV., 1902, p. 175.

G. f/laher Banks. Can. Ent., Vol. XXXIV., 1902, p. 170.

From dry gall, Washington, D. 0.

Genus Oribatodes Banks.

Orihatodes Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 10.

O. miralilis Banks. Trans. Amer. Ent. Soc, Vol, XXII., 1895, p. 10.

In rotten debris. Sea Cliff, N. Y.

Genus Oribatella Banks.

Orlhalrlln Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1S95, p. 8.

O. aquatica Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 9.

On aquatic plants, Sea Cliff, N. Y.

O. horealis Banks. Insects, etc. Commander Isl., 1899, p. 349.

Glinka, Commander Isl.



380

0. minuta Banks. Trans. Amer. Ent. Soc, A^ol. XXIII. , 1896, p. 76.

Under bark, Sea Cliff, N. Y.

0. ohesa Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 9.

Olympia, Wash.

0. ovalis C. L. Koch ( Oribates). Crust. Myr. Arach., Heft 3, Tab. 5.

Under old boards, Areola, 111.

0. perfec'ta Banks. Trans. Amer. Ent. Soc, Vol. XXIII., 1896, p. 75.

Swept from low herbage, Pine Island, N. Y. ; Norfolk, Va.

0. quadridentata Banks. Trans. Amer. Ent. Soc, Vol. XXII.,

1895, p. 8.

Under boards, Urbana, 111. ; Sea Cliff, N. Y.

0. setosa Banks. Jour. N. Y. Ent. Soc, 1895, p. 129.

From wet Sphagnum, Roslyn, N. Y.

0. signata Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 9.

Sea Cliff, N. Y.

Genus Oribata Latreille.

This is the Oribata used in Michael's "Oribatidse" (Das Tier., Lief. 3). Since

the pubUcation of that work in 1898 Dr. A. C. Oudemans has stated that the Oribata

of Latreille is not, in his opinion, the Oribata of "Das Tierreich", but is a Daitums,

and he gives the name Notaspis Herm. to this genus.

0. (iMnis Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 6.

Under loose bark, Washington, D. C.

0. alata Packard. Cave Memoir, 1887, p. 42.

Dixon's Cave, Ky.

0. americana Haller. Arch. Naturg., Jahrg. 50, Bd. I., p. 222, Taf.

XV., Fig. 4.

America.

0. arhorea Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 7.

On cedar- and peach- trees, Sea Cliff, N. Y.

O. armipes Banks {Galumna). Proc Acad. Nat. Sci. Phila., 1906,

p. 492.

Falls Church, Va., and Fort Lee, N. J.

0. artilamellata, n. sp.

Areola, 111.



381

0. hanJtsI, n. sp.

Under bark of trees, ]\[artinsville, Marshall, Urbana, and Ha-
vana, 111.; in moss. Areola, 111.

O. cent)'o-americana Stoll. Biol. Centr. Amer., Arach. Acar., p. 21,

PI. XV., Fig. 1.

British Honduras.

O. clavilanceolata Ewing. Psyche, Vol. XIV., p. 112.

Under stones, Batavia, 111.

O. clavipectinata Ewing. Psyche, Vol. XIV., p. 112,

In moss, near Chicago, 111.

0. curva Ewing. Psyche, Vol. XIV., p. 113.

Under logs, near Chicago, 111.

O. depressa Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 0.

Sea Cliff, N. Y.

0. emarginata Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1805,

p. 7.

Under old logs, Urbana, Areola, and Marshall, III, ; in moss.

Sea Cliff, N. Y. ; Brazos county, Texas.

O. fiiscipes C. L. Koch. Crust. Myr. Arach., Heft (>, Tab. 8.

In moss, New YorkState(?) ; under old pieces of wood, Areola, 111.

0. ///m(/rt Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 7.

Under dead leaves. Sea Clid', N. Y.

O. illinoise7}sis, n. sp.

Areola, 111.

O. impel'fecta Banks {Galimina). Proc Acad. Nat. Sci. I'hila.,

1906, p. 492.

Indianapolis, Ind.

O. magna Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 0.

Sea ClifF, N. Y.

O. inlnuscula Bdiuk^ (Galiwina). Proc. Acad. Nat. Sci. Phila.,

1906, p, 492.

From young peach- and apple- trees, Alma, 111. ; Bay Ridge, Md.

O. mcesta Banks, Trans. Amer. Ent. Soc, Vol. XXII, , 1895, p, 6.

On the ground, Sea Cliff, N. Y.



882

O. multipilosa Ewing. Psyche, Vol. XIV., p. 113.

Under logs, near Chicago, 111.

O. nitiflula Banks {Galumna). Proc. Acad. Nat. Sci. Phila., 1906,

p. 491.

Franconia, N. H.

0. octopunctata^ n. sp.

In moss, Homer, 111.

. pallida Vid.\\V?> {Orlhatula). Proc. Acad. Nat. Sci. Phila., 1906,

p. 494.

Fort Lee, N. J.

O.palustris Banks. Jour. N. Y. Ent. Soc, 1895, p. 128.

From wet SphagniDn., Roslyn, N. Y.

0. pari^ilamellata., n. sp.

Homer, 111.

O. 2)e7'similis Banks {Galumna). Proc. Acad. Nat. Sci. Phila.,

1906, p. 491.

Franconia, N. H.

0. yTatensis Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895. p. 6.

On grass, Sea Cliff, N. Y.

O. rohusta Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 7.

Under bark of walnut, Urbana, 111. ; Sea Cliff, N. Y. ; Fort Lee,

N. J. ; Washington, D. C.

0. rugifrons Stoll. Biol. Centr. Amer., Arach. Acar., p. 25, PL
XV., Fig. 2.

British Honduras.

0. slosisonce Banks {Galuinna). Proc. Acad. Nat. Sci. Phila.^ 1906,

p. 490.

Franconia, N. H.

O. spinogenuala.^ n. sp.

Areola, 111.

0. texatia Bsinks { Galumna). Proc. Acad. Nat. Sci. Phila., 1906,

p. 494.

San Antonio, Tex.

0. turgida Bs^nks (Galumna). Proc. Acad. Nat. Sci. Phila., 1906,

p. 493.

Palm Springs, Calif.



3S3

0. unh/tari/hfta Bsinks {Galumurf). Proc. Acad. Nat. Sci. IMiila.,

1900, p. 490.

Under boards, Areola, 111.; Franconia, N. H.

O. viry'inira Banks {GaUoima). Proc. Acad. Nat. Sci. Phila., 190(5,

p. 493.

Under old pieces of wood and under bark. Homer, 111. ; Falls

Church, Va.

Family NOTHRID^.

Genus Ltacarus Michael.

iiooarws Michael. Das Tier., Lief. 3, 1898, p. 40.

Z. ahdominalis Banks. Proc. Acad. Nat. Sci. Phila., 1900, p. 495.

Claremont, Calif.

L. caroJinensis Banks. Proc. Acad. Nat. Sci. Phila., 1900, p. 494.

Black Mountain, N. C.

L. frontalis Banks. Proc. Acad. Nat. Sci. Phila., 1900, p. 495.

Falls Church, Ya.

Z. (jIoh(fer P. Kramer {Leisoma). Bibl. Zool., Vol. XX., 1897, p. 80.

Greenland.

Z. luculus, n. sp.

Areola, 111.

Z. minuti's^ n. sp.

Urbana, 111.

Z. itiodestus Banks. Proc. Calif. Acad. Sci., Ser. 8, Vol. III., 1904,

p. 307.

Los Angeles, Calif.

Z. )i'i<jer^ n. sp.

In moss, Homer, 111.

Z. nitidus Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 10.

Quite common on ground under wood, bark, stones, etc., Sea
Cliff, N. Y. ; Fort Lee, N. J.



384

Genus Notaspis Hermann.

Notaspis Hermann. Mom. Apterol., 1804, p. 87.

]V. arctica Banks {Eremcuus). Insects, etc., Commander Isl., 1899,

p. 849.

Glinka, Commander Isl.

N. hurrowsi Mich. Proc. Zool. Soc. Lond., 1890, p. 418, PI. XXXVII.,
Fig. 1-4.

Lake Winnipeg, Canada.

iV. canadensis ^di,\\\^B (Oppla). Proc. Acad. Nat. Sci. Pliila., 1906,

p. 497.

Ottawa, Canada.

N. carljonaria Banks. Proc. Acad. Nat. Sci. Phila., 1906, p. 496.

Humboldt, Calif.

N. Uoridana Banks {Eremcmis). Proc. Acad. Nat. Sci. Phila., 1904,

p. 145.

Punta Gorda, Fla.

N. montana Banks {Oppla). Proc. Acad. Nat. Sci. Phila., 1906,

p. 497.

Franconia, N. H.

N. pllosa Banks {SctUovertex). Trans. Amer. Ent. Soc, Vol. XXII.,

1895, p. 11.

Under bark of trees. Sea Cliff, N. Y. ; Fort Lee, N. J.

N. punctidata Banks {Cepheus). Trans. Amer. Ent. Soc, Vol.

XXII., 1895, p. 10.

In decaying fungus and in weeds. Sea Cliff, N. Y.

N. pyrostigina^ n. sp.

Areola, 111.

N. spinipes Banks {Oppla). Proc. Acad. Nat. Sci. Phila., 1906,

p. 496.

Falls Church, Va.



385

Genus Scutovertex Michael.

Scutovertex MichsieL Jour. Roy. Micr. Soc, Vol. II., 1879, p. 241.

S. marinus Banks (Nothrus). Trans. Amer. Ent. Soc, Vol. XX III.,

1896, p. 77.

On rocks between tide marks, Sea Clifl', N. Y.

S. petrophagus Banks. Ent. News, Vol. XVII. , 1006, p. 194.

In cavities in the surface of wet rock, Traghanic [Taughannock?]
Falls, N. Y.

Genus Tegeocranus Nicolet.

Tegeocmmis Nicolet. Arch. Mus. Paris, T. VII., 1855, p. 164.

T. lamellatus Banks {Cepheus). Proc. Acad. Nat. vSci. Phila., 1906'

p. 497.

Falls Church, Va.

Genus Oarabodes C. L. Koch.

Carabodes C. L. Koch. Crust. Myr. Arach., Heft 3, 1885.

C. apicalis Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. lo.

Sea Cliff, N. Y.

C. hrevis Banks. Trans. Amer. Ent. Soc, Vol. XXIII., 1896, j). 77.

Dead fungus. Sea Cliff, N. Y.

C. dorsalls Banks. Trans. Amer. Ent. Soc, \o\. XXIII., 1896, p. 77.

Sea Cliff, N. Y.

C. gramdatus Banks. Jour. N. Y. Ent. Soc, 1895, p. 129.

From wet Sp/iagHf//n, Roslyn, N. Y.

C. nlger Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 12.

In decaying fungi and under bark. Sea Cliff, N. Y.

C. ohlongiis Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 18.

Under bark. Sea Cliff", N. Y.

Genus Dam.eus C. L. Koch.

Damn us C. L. Koch. Crust. Myr. Arach., Heft 3, 1835.

D. angustipes Banks {(Jrihata). Proc. Ent. Soc Wash., Vol. VII.,

1906, p. 136.

In dead leaves, Mt. Vernon, Va.



386

D. anstralis Bsinks (Belba). Trans. Amer. Ent. 8oc., Vol XXII.,

1895, p. 12.

Shreveport, La.

I?, hulhijyedatus Packard. Cave Memoir, 1887, p. 42.

End of Dixon's Cave, Ky.

I), californicus Banks (Orlbata). Proc. Calif. Acad. Sci., Ser. 3,

Vol. III., 1904, p. 367.

Mt. Shasta, Calif.

D. iJoridanus Banks {Belba). Trans. Amer. Ent. Soc, Vol. XXIII.,

1896, p. 76.

Punta Gorda, Fla.

D. longiseta Banks {Orlbata). Proc. Acad. Nat. Sci. Phila., 1906,

p. 498.

Falls Church, Va.

jD. nitens C. L. Koch {Oppia). Crust. Myr. Arach., Heft 3, Tab. 10.

Urbana, 111.

D. p>uritanicus Banks {Orlbata). Proc. Acad. Nat. Sci. Phila.,

1906, p. 498.

Middlesex Fells, Mass.

D. suMexus Michael. Jour. Roy. Micr. Soc, Ser. 2, Vol. V., 1885,

p. 394.

In moss, Dedham, Mass.

Genus Hermannia Nicolet.

IfeniKtnnia Nicolet. Arch. Mus. Paris, T. VII., p. 468, 1855.

II. quadrlseriata Banks. Insects, etc.. Commander IsL, 1899, p. 349.

Glinka, Copper Isl.

//. trlnebulosa Riley. Hubbard's Orange Insects, 1885, p. 216.

Genus Neoliodes Berlese.

yeuliodes Berlese. Bull. Soc. Ent. Ital., Vol. XX., 1888, p. 47.

JV. concentrica Say. Jour. Phila. Acad., Vol. II., 1821, p. 73.

Under bark of elm-tree, Washington, D. C. ; Enterprise, Fla.

;

and from Pennsylvania.

R. fforldensls Banks. Proc. Acad. Nat. Sci. Phila., 1906, p. 499.

Lake Worth, Fla.



387

Genus Tumidalvus Ewing.

Tiimidalrus Ewing. Ent. News, Vol. XIX., 1908, No. 6, p. 24:5.

T. amerieana Ewing. Ent. News, Vol. XIX. , 1908, No. 6, p. 244.

In moss, Areola, 111.; in rubbish, Columbia, Mo.

Genus Cymb.t:rem.eus Berlese.

CymhirremiYus'Berleiie. Acari, Myr., Scorp., Ease. LXXVIII., 1890.

C. marginalis Banks {Eremceiis). Trans. Amer. Ent. Soc, Vol.

XXIII., 1896, p. 76.

On bark. Sea Clifl", N. Y.

Genus Nothrus C. L. Koch.

Xothrus C. L. Koch. Crust. Myr. Arach., Heft 2, 1835.

JV. hanksi Michael. Das Tier., Lief. 3, 1898, p. 70.

Olympia, Wash.

N. Upilis Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 14.

From Sphagnum^ Sea Cliff, N. Y.

N. excisus Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895, p. 15.

On the bark of spruce-trees, Sea Cliff, N. Y.

JV. rugulosus Banks. Trans. Amer. Ent. Soc, Vol. XXII., 1895,

p. 15.

Under bark. Sea Cliff, N. Y.

N. simplex Banks. Jour. N. Y. Ent. Soc, 1895, p. 130.

From wet Sphagnum, Roslyn, N. Y^

iV. taurmus Banks. Proc Acad. Nat. Sci. Phila., 1906, p. 499.

Falls Church, Va.

N. truncatus Banks. Trans. Amer. Ent. Soc, VoL XXII., 1895, p. 14.

From SpJiagnurn and in moss, Sea Cliff, N. Y.

Genus Hypochthonius C L. Koch.

Hypochthonlus C. L. Koch. Crust. Myr. Arach., Heft 3, 1835.

//. rufulus C. L. Koch. Crust. Myr. Arach., Heft 3, Tab. 19.

Areola, 111.



388

Family HOPLODEKMID^.

Genus Hoploderma Michael.

Hoploderma Michael. Das Tier., Lief. 3, 1898, p. 77.

//. dasypus Ant. Duges ( Oribates). Ann. Sci. Nat., Ser. 2, Vol. II.,

p. 47.

In decayed wood, Areola, 111.

//. granulatum Banks. Can. Ent., Vol. XXXIV., 1902, p. 175.

Ottawa, Canada.

11. setosum. Bd^nks, {Hoplophora). Trans. Amer. Ent. Soc, Vol.

XXII., 1895, p. 16.

On the ground. Sea Cliff, N. Y.

H. sphcBVuhim Banks {Hoplophora). Trans. Amer. Ent. Soc, Vol.

XXII., 1895, p. 16.

Sea Cliff, N. Y.

Genus Phthiracarus Perty.

Phthiracartts Perty. Allg. Naturg., III., 1841, p. 874.

P. americanus^ n. sp.

Under logs and old boards, Danville, Areola, and Urbana, 111.

P. arctatus Riley {HoplopJwra). Riley's 6th Mo. Rep., 1874, p. 53.

Sea Cliff, N. Y. ; Florida; Missouri.

P. cryptopus Banks. Proc. Calif. Acad. Sci., Ser. 3, Vol. III., 1904,

p. 367.

Claremont, Calif.

P. Hagelliformis^ n. sp.

Under logs, Homer, 111.

P. iJavus Ewing. Ent. News, Vol. XIX., p. 450.

In moss, Urbana, 111.

P. glabratus Say. Jour. Phila. Acad., Vol. II., 1821, p. 73.

Sea Cliff, N. Y.

P. magnus Ewing. Psyche, Vol. XIV., 1907, p. 114.

Under old logs, Pine, Ind.

P. rotundus Ewing, Ent. News, Vol. XIX., p. 451.

Under a log, Batavia, 111.



389

EXPLANATION OF PLATES.

Pr,ATE XXXIII.

Fig. 1. (h-ibala.tplnogenmla, n. sp., X 34; \a, pseiulostigmatio organ ; 1^, bristle

on the tip of the genual of leg II; h; anal and genital covers.

Fig. 2. Orihala nrt'damelUtln, n. sp., X 34; 2<i, psendostigmata and pseiidostig-

mati<; organ.

Fig. 3. OrlhaUi illlnol.seiisls, n. sp., X 58; 3(j, pseudostigmata and pseudostig-

niatic organ.

Fig. 4. Orlbata rohustn Banks, X 34; -ia, j)sendostigmata and psendostiginatio

organ; 46, anal and genital covers.

Plate XXXIV.

Fig. ."). Orihata rirginica Banks, X 58; 5<i, psendostigmata and iinendostig-

niatie organ.

Fig. 6. Oribata jjarrllamellata, n. sp., X 34; 6<t, psendostigmata and pseiidostig-

matic organ; 66, ventral surface.

Fig. 7. Oribata octopnncfnta, n. sp., X 58; 7a, psendostigmata and psendostig-

matic organ.

Fig. 8. Oribata minuscula Banks, X 34; i>a, psendostigmata and jisendostig-

matic organ; 86, anterior ends of lamelhi' and the translamella.

Fig. 9. Liacanifi lucidus, n. sp., X 58; 9a, pseudostigmata and pseudostiguiatic

organ.

Plate XXXV.

Fig. 10. Lt((rarus hiiniilns, n. sp., X 58; 10'(, psendostigmata and pseudostig-

matic organ.

Fig. 11. JJacariis niyer, n. sp., X 34; llo, pseudostigmata and pseudostigmatic

organ.

Fig. 12. Nofaapis jnjroi^tupna, n. sp., X 58; 12a, pseudostigmata and pseudo-

stigmatic organ; 126, palpus and mandible.

Fig. 13. Phthiracarus JiageUifontus, n. sp., X 34; 13rt, pseudostigmata and

pseudostigmatic organ; 136, mandible; 13c, distal end of tarsus of leg I.

Fig. 14. Phthiracarus aviericanm, n. sp., X .34; 14«, pseudostigmata and pseudo-

stigmatic organ; 146, distal end of tarsus of leg I.

Ismcd September 25, 1909.

ERRATUM.

Page 378, line 1, for XXV. read XA'AT.



XXXIII.

©

H. E. E. del.

ILLINOIS ORIBATOIDEA.



XX XIV.

H. K. E. tie

ILLIXOrS ORIBATOIDEA.



)i^XXV

H. E. E. del.

ILLINOIS ORIBATOIDEA.