Bulletin

OF THE

Illinois State Laboratory

OF

Natural History

Urbana, Illinois, U. S. A.

Vol. VIII. August, 1908 Article II.

NEW GENERA AND SPECIES OF ILLINOIS THYSANOPTERA

BY

J. DOUGLAS HOOD



ERRATA AND ADDENDA.

Page 58, line 7, for ovalis read ovata.

Page 85, line 8, for longicaiidiis read longicanda, and just above Phaciis plcitro-

nectes read the following paragraph :

—

Phacus longicanda var. torta. n. var.—This variety, for which I propose the

name torta because of the twisted body, is figured by Stein ('78, Taf. 20, Fig. 3). It

occurred sparingly in midsummer from July to September, rarely in October, in

1896 and 1897.

Page 91, line 18, after T. caudata Ehrb. read T. lagenella Stein.

Pages 153, line 3 from bottom, 168, line 16, and 178, line 14, iov'98 read '.9Sa.

Pages 156, line 11, 159, line 16, and 161, line 5 from bottom, for '93 read '98a.

Pages 175, line 5, 186, line 3, and 208, line 17, for Bimcerium read Dimcerium.

Page 288, line, 3 for Lampsilus read Lampsilis.

Page 292, line 13, for gracilis read gracile.

Page 471, line 3 under heading beetles, for pennsylvanicus read pennsylvanica



Article II.

—

Neiv Ge^iera and Species of Illinois Thysanoptera.

By J. Douglas Hood.

In the present paper, descriptions are given of five new genera

and fifteen new species of Illinois Thysanoptera. For much of the

material upon which these descriptions are based, I am indebted to

se\-eral of my friends and associates, among whom may be mentioned

Charles A. Hart, Robert D. and Hugh Glasgow, John J. Davis, Lindley

M. Smith, Henry E. Ewing, James Zetek, Frank C. Gates, and George

H. Coons.

In the measurements, non-chitinous portions have been excluded.

For example, the length of the prothorax is taken to be its length

along the median dorsal line, exclusive of the membrane connecting

it with the head.

Type specimens are in the writer's collection, and in the collection

of the Illinois State Laboratory of Natural History.

Suborder TEREBRANTIA Haliday

Family THRIPID.^ Uzel.

Heterothrips gen. nov. (Fig. 1.)

(erepos, other than usual; dpiip, thrips.)

Head wider than long. Ocelli present. Antennae
clearly nine-segmented; segments 3 and 4 conical,

large, their combined lengths about equal to that

of segments 5-9, each with an apical band enclos-

ing small circular sensoria (?), disposed in two nearly

regular transverse rows; segments 5-9 much nar-

rower than 3 and 4, successively diminishing in

diameter; segments 5-8 provided each with either

one or two slender sense cones. Maxillary- palpi

three-segmented. Prothorax twice as long as head,

sides decidedly arcuate; not armed with long spines.

Second fore tarsal segment armed with a claw-

like appendage. Fore wings long, narrow, pointed,

with two longitudinal veins, separate for their

entire length, and set with from 20 to 24 stout

spines ; costa similarly armed with stout spines which

361

Fic. 1

Heterothrips ariscemce,
female, a, left anten-
na, dorsal view; 6,

right fore tarsus, out-
er side. (J. D. H..
del.)



362

gradually increase in length toward apex of wing. Sides of abdomen
reticulate, sparsely spinose; posterior margins of abdominal segments
2-8 prolonged into small equidistant flattened spines (excepting under
the wings), which may be united at their bases into plates; tip of abdo-
men (in female) conical, tenth segment weakly chitinized in its apical

median half; ovipositor well developed, curved downwards.

This genus, although seemingly a specialized one and suggest-

ing Sericothrips Haliday, has retained certain primitive characters

(the nine-segmented antennae, the character of the sensoria, and the

tarsal appendage) which indicate affinities with the yEolothripidce.

In view of the fact that in all the species of the order, a change in the

number of antennal segments always consists in a reduction and
never in an increase in the number of these segments, it might be

assumed that the Thripidas early divided into two branches, one of

which, continuing more nearly along the original line, gave rise to the

present genus, while the other produced the ordinary type of Thrip-

id£e. Heterothrips is, indeed, so sharply separated from all other

members of its family, that a new sub-family might easily be erected

for it ; but it seems best to defer this until the Thripidae are better

known.

Heterothrips ariscBmcB sp. nov. (Fig. 1.)

Female.—Length about 1.25 mm. Color nearly uniform dark
blackish brown; tarsi, anterior tibiae, and third antennal segment pale

yellowish.

Head rather coarsely transversely striate, faintly but sharply con-
stricted at posterior margm of eyes; frons acutely emarginate. Antennal
segments 1 and 2 slightly lighter than body, shaded laterally with black,

the former provided with a sub-transverse carina; segment 3 pale yellow-

ish, with a narrow sub-basal white band, and apical third clouded with
brown; segments 4-9 uniform light blackish brown, excepting the yellow-

ish sub-apical band of sensoria on segment 4.

Prothorax about twice as long as head and two-thirds as long as

wide; sides and angles rounded; surface sparsely spinose, and faintly

reticulate. Pterothorax about 1 . 3 times as wide as prothorax, and
about as long as wide; mesoscutum transversely striate, and with four

pairs of short spines; metascutum concentrically striate. Wings just

attaining tip of abdomen; basal third widened, the sub-basal width
slightly more than twice the sub-apical, and contained in the total length

about 7.6 times; color blackish brown, excepting a broad sub-basal

white band. Legs reticulate; femora nearly concolorous with body, the

anterior pair shading to yellow at apex; fore tibiee yellow, shaded later-



363

ally wiih brown; middle and hind tibiae blackish brown, extremities
paler; all tarsi clear yellow.

Abdomen lanceolate, widest at segment 4; spines short, inconspic-
uous.

Measurements:—Total length 1.24 mm.; head, length .10 mm.,
width .18 mm.; prothorax, length .16 mm., width .24 mm.; pterothorax,
width .32 mm.; abdomen, width .34 mm. Antennae: 1,28/^; 2, 42 n;
3, 84 ,«; 4, 56 ,«; 5, 34 /<; 6, 34 ,«; 7, 25 fi; 8, 22 ,«; 9, 25 //; total, .37 mm.

Male.—Length .72 -.80 mm.; prothorax, length . 14 mm., width .22
mm.; mesothorax, width .22 mm.; abdomen, width . 19 mm.

Brachypterous. Last ventral segment of abdomen with a broad,
semicircular emargination, each side of which is an acute tooth.

Described from twelve females and two males, taken at Urbana,
Illinois, in flowers of Jack-in-the-pulpit {AriscBma triphyllum) , by Mr.

Frank C. Gates.

Genus Sericothrips Haliday, 1836.

Sericothrips pulchellus sp. nov.

Female.—Length about 1 mm. Color dark blackish brown to black,
with bright red hypodermal pigmentation.

Similar to 5. variabilis (Beach), differing from it as follows:

Head uniform gray-black. Antennal segments 1 and 2 dark blackish
brown, the latter grayish yellow at middle; segments 3, 4, and 5 grayish
yellow, 5 slightly clouded apically; segments 6-8 gray, the basal third

of 6 grayish yellow.

Prothorax concolorous with head, with conspicuous black reticula-

tion, and thickly dotted with black spots, the latter visible only under
high power. Pterothorax nearly concolorous with prothorax, the red
pigmentation usually quite conspicuous. Fore wings black, tipped with
white, and with two broad white cross bands, one near base, other near
apex. Femora nearly concolorous with body, pale basally; ground,
color of tibiae pale yellow, the fore pair clouded basally and laterallv with
brown; middle and hind pairs pale at extreme base, beyond which they
are concolorous with the femora to, or slightly beyond, middle; tarsi pale
yellow.

Abdomen often pale at middle, and with segments 7-10 darker.

Measurements:—Total length 1.0 mm.; head, width .17 mm.; pro-

thorax, length .14 mm., width .21 mm.; mesothorax, width .28 mm.;
abdomen, width .31 mm. Antennae: 1, 22 //; 2, 39 //; 3, 62 /<; 4, 59 //;

5, 48 //; 6, 53 /jt; 7, 11 /z; 8, 14 /<; total, .31 mm.
Male.—Length about . 7 mm. Coloration similar to that of female.

This species is very close to 5. variabilis (Beach), but the colora-

tion is distinctive. In living specimens, examined under a hand lens,



364

the head and prothorax are velvety-black and without luster, due no

doubt to the microscopic reticulation.

At Muncie, Illinois (the only locality from which I have seen speci-

mens) this species was very abundant upon the hop tree {Ptelea tri-

foliata). As many as fifty individuals were frequently observed on
the under surface of a single leaf, where their peculiar coloration

rendered them very conspicuous.

Female.

Suborder TUBULIFERA Haliday.*

Family PHLOEOTHRIPID^ Uzel.

Genus Zygothrips Uzel, 1895.

Zygothrips longiceps sp. nov. (Fig. 2).

-Similar to Z. minutus Uzel. from which it differs as follows:

a. Length about LI mm. head about LI times as long as wide, half as long as
antennae, and about 1.4 times as long as tube. Anterior marginal spines

on prothorax large, subequal in length
to the others. Posterior margins of

abdominal segments 3-7 provided each
with two pairs of straight spines, the
inner pair short. Tarsi light yellow, tibise

yellowish, the first and third pairs
clouded at base, and the second pair at
middle, with brown or black

Z. minutus Uzel.
aa. Length about L47 mm. Head about 1.4

times as long as wide, three-fifths as
long as antennas, and almost twice as
long as tube. Anterior marginal spines
on prothorax wanting. Posterior mar-
gins of abdominal segments 3-6 pro-
vided each with two pairs of long spines,
the inner pair sigmoid. Tibiae and
tarsi uniform bright yellow

Z. longiceps sp. nov.

Fig. 2

Zygothrips longiceps, female, head and
prothorax. (J. D. H., del.)

The measurements of the female of

this species are as follows: Total length

1.47 mm.; head, length .192 mm., width
.134 mm.; prothorax, length .123 mm.,
width (including coxae) .232 mm.; ptero-

thorax, width .234 mm.; abdomen, width .272 mm.; tube, length .102

*The division of the Tubulifera into the two families PhlceothripidcB and
IdolothripidcB, proposed by R. S. Bagnall (Ann. and Mag. of Nat. Hist., Eighth
Series, Vol. I., No. 4, p. 356; Apr., 1908), seems to be an unnatural one, apparently
separating from each other species which are more closely related than the ex-
tremes of the respective families into which they fall.



365

mm., width at base .057 mm., at apex .032 mm. Antennae: 1, 24 //;

2, 44: pi; 3, 44 //; 4, 46,«; 5, 45 //; 6, 41 /x; 7, 38//; 8, 24,«; total, .30 mm.

Described from a single brachypterous female taken by the writer

in a gall on Solidago, at Carbondale, Illinois, June 20, 1907.

LissoTHRiPS gen. nov.

{XcGobs, smooth ; dpc<p, thrips.)

Head slightly wider than long, sub-globose, narrowed posteriorly;

eyes directed forwards; cheeks full, sparsely spinose. Antennae about
twice as long as head, eight-segmented; segments 1 and 2 broadest; 3

ver}^ small, shorter and narrower than any of the following segments,
excepting the distal one-; 7 longest. Mouth cone broad, pointed, sur-

passing base of prostemum. Prothorax shorter than head, with five

pairs of ver}' long bristles. Fore tarsi unarmed.

This genus is closely related to Cephalothrips Uzel, but the longer,

pointed mouth cone and the structure of the antennae are sufficiently

distinctive to warrant the erection of a new genus.

Lissothrips muscorum sp. nov.

Female.—Length about 1.17 mm. Color blackish brown to black,

legs and antennal segments 1 and 2 paler.

Eyes moderate in size, coarsely faceted, situated on anterior surface

of head. Ocelli lacking. Postocular spines long, blunt, expanded
distally.

Prothorax three-fourths as long as head; spines slightly expanded at

tips ;|mid-lateral spines and the pair at the posterior angles almost as

long as prothorax. Pterothorax about as long as, and slightly narrower

than prothorax; mesonotum with one long spine at each posterior angle.

Abdomen one and one-third times as wide as prothorax; posterior

borders of abdominal segments 2-9 each with two pairs of very long, sub-

equal, pointed bristles, some twice the length of the abdominal segments,

f Measurements:—Total length about 1.17 mm.; head, length .16

mm., width . 17 mm.
;
prothorax, length . 12 mm., width (including coxae)

.28 mm.; pterothorax, width .26 mm.; abdomen, width .36 mm.; tube,

length . 12 mm., width at base .070 mm., at apex .034 mm. Antennae:

1, 25 /x; 2, 43 /<; 3, 32 fi; 4, 42 /x; 5, 42 /x; 6, 46 /x; 7, 48 /x; 8, 36 /x; total,

.31 mm.

Described from several apterous females, from Areola, Dubois,

Mahomet,'' Marion, Muncie, Pulaski, and Urbana, Illinois, taken in

moss.



366

Genus Trichothrips Uzel, 1895.

Trichothrips americanus sp. nov. (Fig. 3).

Female.—Forma brachyptera.—Length about 1 . 7 mm. General
color clear brownish yellow with more or less dark hypodermal pigmen-
tation

;
prothorax and basal abdominal segments slightly darkened with

brownish black; tube tipped with gray.

Head slightly. longer than wide; vertex elevated, rugose, sloping ab-
ruptly to bases of antennae; cheeks rounded, faintly reticulate, sparsely

spinose; postocular bristles slender, pointed. Eyes reduced. Ocelli want-
ing. Antennas slightly more than twice as long as head; segments 1 and
2 concolorous with body, shaded laterally with black; 3-8 uniform dark
blackish brown, excepting extreme base of 3, which is yellow; 3 sub-
conical; 4-7 oblong, pedicellate, subequal in length, but becoming gradu-

ally narrower; 8 lanceolate, pedicel-

late ; segments 3 and 4 each with two
outer sense cones and one inner one;

5 and 6 each with one sense cone on
either side of apex, the outer one on
segment 6 very small. Mouth cone
just attaining base of prostemum;
labium broadly rounded; labrum
pointed, surpassing labium by the
length of the maxillary palpus.

Prothorax slightly shorter than
head, and (including coxae) about
twice as wide as long; all spines

present, long, pointed. Pterothorax
about as long as, and usually some-
what narrower than, prothorax.
Wings short, attaining base of abdo-
men. Legs about concolorous with
body, all femora shaded laterally

with brown or black; tarsal cups
black; fore tarsi armed with a small,

acute tooth.

Abdomen large, heavy, about one and one-third times as wide as

prothorax. Tube slightly shorter than head, twice as wide at base as

at apex.

Measurements:—Total length 1.68 mm.; head, length .21 mm.,
width . 19 mm.; prothorax, length . 18 mm., width (including coxae) .38

mm.
;
pterothorax, width .36 mm. ; abdomen, width . SO mm. ; tube, length

. 18 mm., width at base .098 mm., at apex .045 mm. Antennae:!, 36 //;

2, 56 fx; 3, 62 ji; 4, 59 /«; 5, 62 //; 6, 59 jx; 7, 57 //; 8, 57 /i; total, .45 mm.
Forma macroptera.—Similar to forma brachyptera in size; general

color darker, the entire body shaded with grayish brown.

Fig. 3

Trichothrips americanus, female, a, head and
prothorax, brachypterous form; b, tip of
right antenna, dorsal view, brachypterous
form; c, head, macropterous form. (J. D. H.
at J. Z., del.)



367

Head broadly rounded in front. Ocelli present. Eyes large, finely

faceted. Pterothorax wider than prothorax. Wings large, reaching
base of tube; color light gray-brown, spotted with darker.

Male (Forma brach3'ptera).—Similar to female, but smaller (length
about 1 .4 mm.). Prothorax about as long as head. Fore tarsi armed
with a slightly larger tooth. Abdomen slender, tapering more gradually
to apex.

Described from several specimens from Carbondale, Homer, and
Urbana, Illinois, taken under bark on rotten stumps.

\

Trichothrips angusticeps sp. nov. (Fig. 4).

Female.—Length about 1.4 mm. General color brownish yellow
with considerable maroon-colored hypodermal pigmentation; head, pro-
thorax, sides of abdomen, and tip of tube slightly darkened with brown-
ish black.

Similar to T. americanus sp. nov., differing from it as follows:

Head fully 1 .4 times as long as wide; cheeks paral-

lel; postocular bristles knobbed. Antennas 1.7 times
as long as head, nearly concolorous with darker parts

of body, excepting segments 1 and 2, and basal half

of 3, which are paler. Mouth cone considerably sur-

passing base of prosternum ; labrum surpassing labium
by twice the length of the maxillary palpus.

Prothorax about . 7 as long as head ; all spines pre-

sent, long, knobbed. Legs yellow, all femora shaded
slightly with brownish.

Abdomen rather slender; tube .6 as long as head.
Measurements:— Total length 1.44 mm.; head,

length .22 mm., width .16 mm.; prothorax, length
.16 mm., width (including coxae) .34 mm.; ptero-
thorax, width .30 mm.; abdomen, width .42 mm.; tube,

length . 14 mm., width at base .081 mm., at apex .038
mm. Antennas: 1, 31 ix; 2, 49 ji; 3, 53 /«; 4, 50 /i; 5,

53 ,«;
6" 50 ,«; 7, 48 //; 8, 50/«; total, .3S mm.

Male.—Similar to female, but smaller (length about 1.25 mm.).
Prothorax five-sevenths as long as head.

Described from eight brachypterous specimens, one of which is a

male, taken under bark on rotten stumps, at St. Joseph and Urbana,

Illinois, by ]\Ir. C. A. Hart and the writer.

Fig. 4

Trichothrips angus-
ticeps, female,
b rachyp terous
form. o, head;
b, tip of right an-
tenna, dorsal
view. (J. D. H.,
del.)



368

Trichothrips longituhus sp. nov.

Female.—Length about 1 . 8 mm. General color dark blackish brown
to black, pterothorax and basal abdominal segments usually paler;

tibiae, tarsi, and intermediate antennal segments bright lemon-yellow,

the tibiae clouded basally.

Head about as wide as long; cheeks slightly converging posteriorly;

vertex elevated, slightly produced, and bearing the anterior ocellus at its

extremity; lateral and dorsal surfaces noticeably transversely striate,

sparsely and briefly spinose; postocular bristles blunt, almost half as

long as head. Eyes slightly more than one-fourth as long as head,

finely faceted. Ocelli anterior; anterior ocellus overhanging. Antennae
slightly less than twice as long as head ; segments 1 and 2 nearly con-
colorous with body, 2 brownish yellow apically; 3-6 uniform bright

lemon-yellow; 7 blackish yellow at base, shading to blackish brown at

apex; 8 blackish brown; sense cones long, slender; segment 3 with one on
outer apical surface; 4-6 each with one on either side of apex, and a

small rudimentary one on dorsum. Mouth cone nearly reaching base of

prosternum.
Prothorax two-thirds as long as head, and (including coxae) about

two and one-half times as wide as long; all spines present, blunt, except-

ing the pair at the posterior angles, which are pointed, and longer than
the prothorax. Pterothorax broader than long, slightly wider than
prothorax; sides arcuate, slightly converging posteriorly. Wings reach-

ing base of tube; fore wings clouded at base, not narrowed at middle, and
with the apical fringe on posterior margin double for about eight hairs.

Legs slender; femora nearly concolorous with body, the middle and hind
pairs paler basally; tibiae lemon-yellow, clouded basally; tarsi lemon-
yellow, unarmed.

Abdomen large, heavy; bristles long. Tube fully as long as head,

tapering evenly from base to apex.
Measurements:—Length 1.84 mm.; head, length .25 mm., width .24

mm.; prothorax, length .16 mm., width (including coxae) .40 mm.;
pterothorax, width .44 mm.; abdomen, width .46 mm.; tube, length .26

mm., width at base . 105 mm., at apex .050 mm. Antennae: 1, 30 /i;

2, 57 //; 3, 73 /<; 4, 68 //; 5, 68 /i; 6, 65 n; 7, 68 /z; 8, 46 /<; total, .48

mm.
Male.—Similar to female. Prothorax and fore femora not en-

larged; fore tarsi unarmed.

Described, from ten macropterous specimens (nine females and one

male) taken in sweepings at Carbondale, Illinois, by Mr. C. A. Hart.

This species is easily distinguished from all other members of its

genus by the peculiar antennal coloration and the long tube.



369

Trichothrips bujfcu sp. nov. (Fig. 5).

Female.—Length about 1.9 mm. General color black; antennal
segments 1-3, tarsi, and articulations of legs, usually yellowish brown.

Head nearly as wide as long, broadly rounded in front; cheeks sHght
ly converging posteriorly; lateral and dorsal surfaces noticeably trans
versely striate, sparsely, briefly, and scarcely visibly spinose; postoculai
bristles blunt, slightly longer than eyes. Eyes almost one-third as long
as head. Ocelli anterior; anterior ocellus scarcely overhanging. An-
tennee slightly more than twice as long as head, faintly reticulate; seg-

ments 4-8 concolorous with body; 1 and 3 usually slightly paler, dark-
ened laterally, the latter pale yellow at extreme base; 2 brownish yellow,
darkened laterally and basally; sense cones long, slender; segment 3 with
one on outer apical surface ; 4-6 each with one on either side of apex and
5 and 6 each with a inidimentary additional one on dorsum ; 7 with a long,

sub-apical one on dorsum. Mouth cone long, attaining base of presternum.
Prothorax about as long as head, and (including coxae) slightly more

than twice as wide as long; all spines present, blunt, the pair at the
posterior angles longest. Pterothorax
rectangular, slightly wider than protho-
rax, and about one and one-third times
as wide as long. Wings short, attaining

base of abdomen. Fore femora not en-

larged; fore tarsi unarmed.
Abdomen large, heavy, 1.3 times as

wide as prothorax, narrowing roundly
from segment 6 to base of tube. Tube
slightly shorter than head, tapering
evenly from base to apex.

Measurements:—Total length 1.87
mm.; head, length .21 mm., width .20

mm.; prothorax, length .19 mm., width
(including coxae) .42 mm.; pterothorax,
width .43 mm.; abdomen, width .54

mm.; tube, length .20 mm., width at

base .094 mm., at apex .042 mm. An-
tenn.e: 1, 30 /x; 2, 56 pt; 3, 64 //; 4, 63 //;

5, 62 n; 6, 63 ft; 7, 62 /x; 8, 42 /.t; total,

.44 mm.
Male.—Similar to female, but smaller (length 1 .5 mm.).

and fore femora not enlarged; fore tarsi unarmed.

Fig. S

Trichothrips huffce, female, head and
prothorax. (J. D. H., del.)

Prothorax

Described from severalbrachypterous specimens of both sexes taken

under bark on soft maple trees at Decatur, Homer, andUrbana, Illinois.

I name this species for Dr. Pietro Buffa, of the Royal University

of Pisa, Italy.



370

Plectrothrips, gen. nov.

{KXrjKxpov, spur; dpc(l), thrips.)

Head slightly longer than wide; cheeks full, without spine-bearing
warts; vertex elevated, transverse. Eyes moderately large. Ocelli pre-

sent, anterior. Antennae inserted beneath vertex, twice as long as head,
eight-segmented; segments 3-6 provided each with two or three short,

stout, roughened sense cones; segment 8 noticeably longer than segment
7, very slender, compressed, provided with a single terminal bristle.

Mouth cone very small, only about one-fourth as long as prothorax,
slightly wider than long, broadly rounded at apex; labrum blunt. Pro-
thorax large, heavy, one and one-third times as long as head, with a
prominent median groove; notum not attaining lateral margins; all

spines wanting, excepting the pair at the posterior angles. Pterothorax
large, lateral outline convex. Legs short, stout; fore tibiae with a stout,

obtuse tooth on inner margin of apex; middle and hind tibiae with re-

spectively one and two long, very stout, tibial spurs on inner lower mar-
gin of apex; anterior femora very large; fore tarsi with a very large,

slightly curved, acute tooth. Wings present, not narrowed at middle.
Male without scale at base of tube.

This genus resembles Trichothrips Uzel in general structure, and
should probably follow it in a linear arrangement of the genera.

Plectrothrips antennatus sp. nov.

Female.—Length, about 1 . 8 mm. General color blackish brown,
fading to brownish yellow on abdomen; tube bright brownish orange.

Head six-sevenths as wide as long, truncate in front, widest behind
eyes, and narrowed posteriorly; lateral and dorsal surfaces very faintly

reticulate, sparsely spinose; postocular bristles slender, pointed, their

bases situated near the lateral margins of head, and equidistant from
posterior margins of eyes and anterior border of prothorax. Eyes finely

faceted, moderately large. Ocelli placed well forward; anterior ocellus

slightly overhanging; posterior ocelli opposite anterior third of eyes and
contiguous to them. Antennae eight-segmented; segments 2-8 sub-
equal in length; 8 compressed, fusiform-pedicellate as seen from above,
and with a single terminal bristle; 3, 5, and 6 provided each with two
short, very stout, roughened sense cones, one on each side of apex; 4 with
an additional similar cone on the outer apical surface; circular sense-area

on segment 2 situated nearer base than usual ; antennae concolorous with

.

body, excepting segment 3, which is orange at base.

Prothorax large, one and one-third times as long as head, and (in-

cluding coxae) two-thirds as long as wide; all the usual spines lacking,

save a single long pointed one at each posterior angle. Pterothorax
slightly broader than long, and a little wider than prothorax; sides

rather prominently arcuate. Wings reaching about to base of tube,



371

veinless; fore wings with an apical double fringe of eight hairs, and with
the basal scale black. Femora concolorous with head and thorax;

tibiae and tarsi yellowish brown.
Abdomen large; sides sub-parallel as far as segment 6, thence curving

roundly to base of tube. Tube about three-fifths as long as head, ab-

ruptlv narrowed at apex, and slightly narrowed at middle.

Measurements:—Total length 1.8 mm. (1.71-1.89 mm.); head,

length .32 mm., width . 19 mm.; prothorax, length .27 mm., width (in-

cluding coxae) .40 mm.; pterothorax, width .41 mm.; abdomen, width
.45 mm.; tube, length . 13 mm., width at base .082 mm., at apex .041

mm. Antennae: 1, 41 ,«; 2, 52 /«; 3, 57 /t; 4, 55 ;«; 5, 54 ;«; 6, 54 /«; 7, 49

fx; 8. 54 /<; total, .42 mm.
Male.—Slightly smaller than female (total length about 1.4 mm.).

Abdomen more slender, tapering more gradually toward apex.

Described from two females and five males, taken by the writer in

June on a window of a wood-shed, Urbana, Illinois.'

This species could not possibly be confused with any other de-

scribed one, distinguished as it is by characters of generic significance.

Neothrips gen. nov. (Fig. 6).

{'j'eos, new; dpc4>, thrips.)

Head almost one and one-half

times as long as wide; cheeks par-

allel, sparsely spinose; vertex ele-

vated, narrowed anteriorly, not
overhanging. Antennae stout, eight-

segmented, about one and three-

fourths times as long as head,
inserted beneath vertex; segments
7 and 8 distinct, but united into

a heavy, compact club, and with
a straight, comb-like, ventral row
of either nine or ten bristles; seg-

ments 2 and 7 slightly longer than
the intermediate ones, which are

almost exactly equal in length.

Mouth cone long, slender, acute,

surpassing base of prostemum;
labrum pointed. Prothorax large,

trapezoidal, armed with five pairs

of bristles. Legs short, stout; fore

tarsi armed with an acute tooth
which in the male is larger and
slightly cun.' ed. Male without scale

at base of tube.

Fig. 6

Neothrips corticis. a, head and prothorax, fe-

male; b, tip of abdomen, female; c, right
antenna, dorsal view, female; (i, right fore leg,

male. (J. D. H., del.)



372

This genus is perhaps more closely related to Allothrips gen. nov.
than to any other, standing between it and Plectrothrips gen. nov.

Neothrips corticis sp. nov. (Fig. 6).

Female.—Length about 1.34 mm. Color nearly uniform light yel-

lowish brown, with considerable irregular reddish brown hypodermal
pigmentation; tube bright orange-brown, darker at middle.

Eyes very small, consisting of a few large, lateral facets; ocelli want-
ing. Antennae nearly concolorous with body, segments 1 and 2 often
slightly darkened laterally; sense-cones long, slender, segments 3 and 6

each with one and segments 4 and 5 each with two; three bristles on
ventral surface of segment 7.

Pterothorax about as wide as prothorax, its dorsum two-thirds as

long as wide. Wings rudimentary. Tarsi and apices of tibiae yellow;

femora and basal three-fourths of tibiae nearly concolorous with body,
lighter along inner surface.

Abdomen large, heavy, about one and one-half times as wide as

prothorax; sides sub-parallel as far as segment 6, and then converging
abruptly to base of tube. Tube . 7 as long as head, and about 1 .4 times
as long as its basal width; abruptly narrowed at apex and slightly nar-
rowed at middle, where it is more heavily chitinized.

Measurements:—Total length about 1.34 mm.; head, length .20

mm., width .14 mm.; prothorax, length (excluding non-chitinous por-

tions) . 15 mm., width (including coxae) .29 mm.
;
pterothorax, width .28

mm.; abdomen, width .42 mm.; tube, length .14 mm., width at base,

.095 mm., at apex, .036 mm. Antennae: 1, 31 [x; 2, 54 p.; 3, 46 fx; 4.

44 /<; 5, 44 jx; 6, 45 p.; 7, 50 [x; 8, 29 //; total, .34 mm.
Male.—Slightly smaller than female (length about 1.2 mm.). Four

bristles on ventral surface of segment 7. Abdomen more slender (about
one and one-fifth times as wide as prothorax), tapering evenly from
segment 7 to base of tube.

Described from several specimens of both sexes taken under
bark at Urbana and Hillery, IlHnois, in winter.

Allothrips gen. nov. (Fig. 7).

{aXXos, of another kind; dpaj), thrips.)

Head large, about as wide as long; cheeks full, sparsely spinose-
vertex elevated between eyes, and sloping abruptly to insertion of

antennae. Antennae stout, seven-segmented, less than 1.6 times as
long as head, inserted beneath vertex; segments 3-6 subequal in

length, very slightly longer than wide; 2 and 7 longer, the latter

with a slightly arcuate row of four bristles on its ventral surface.



373

Mouth cone large, broadly rounded,
reaching base of prostemum; la-

brum blunt. Prothorax short,

about two-thirds as long as head,
and armed with six pairs of knob-
bed bristles. Legs short, stout;

fore tarsi unarmed.

This genus is the only one of

its family (excepting Kladothrips

Froggatt) which has seven-seg-

mented antennae. The reduction

in the number of antennal seg-

ments is a result of the union of

the two apical ones, and the whole

antenna is an exaggeration of the

type indicated by Neothrips gen.

no\'. , in which a separating suture

is still distinctly visible.

Allothrips megacephalus

sp. nov. (Fig. 7).

Female.—Length about L3 mm.
Color dark blackish brown, with maroon-colored hypodemial pigmen-
tation; tarsi, tube, and antennal segments 1 and 2 slightly lighter. Ab-
domen broad, about one and one-half times as wide as prothorax.

Forma aptera.—Eyes ver}^ small, consisting of a few large lateral

facets. Ocelli lacking. Pterothorax about as long as prothorax; meso-
notum transverse, sub-rectangular, with six equidistant knobbed bristles

along its posterior border, and with an additional similar pair near the

posterior angles.

Measurements:—Total length 1.31 mm.; head, length .21 mm.,
width .20 mm.; prothorax, length . 14 mm., width (including coxas) .30

mm.; pterothorax, width .30 mm.; abdomen, width .45 mm; tube,

length . 12 mm., width at base .082 mm., at apex .044 mm. Antennae:

1,38,«;2, 57;<;3, 51/z;4, 41 /x; 5,44//;6, 44/i; 7, 67/z; total, .34 mm.
Forma brachyptera.—Eyes moderately large, coarsely faceted. Ocelli

present; a pair of long knobbed bristles behind the posterior ones.

Pterothorax about twice as long as prothorax ; mesonotum sub-pentago-
nal, with two pairs of knobbed bristles along its posterior border. Wings
attaining base of abdomen.

Described from several females, one of them brachypterous, taken

under bark on various trees at Urbana and Springfield, Illinois, in

winter.

Fig. 7

Allothrips megacephalus, female, apterous form.
a, head and prothora.x; b. right antenna,
dorsal view; c, tip of abdomen. (J. D. H., del.)



374

Genus Acanthothrips Uzel, 1895.

This genus is represented in Illinois by two species, which may
readily be distinguished from each other and from their previously

described congeners by means of the following key.

I. Inner-surface of fore femora with a single sub-apical tooth.

o. Cheeks with prominent spine-bearing warts. No latero-dorsal
white stripe.

b. Wings of both pairs with a very prominent blackish longi-
tudinal vein reaching nearly to tip

A. niagnafemoralis Hinds.*

bb. Wings without conspicuous longitudinal vein
A. doaneii Moulton, A. nodicornis (Reuter).

aa. Cheeks without spine-bearing warts. A latero-dorsal white
stripe A. albivittatus sp. nov.

II. Inner surface of fore femora with a "long, sharp, and slightly curved"
tooth near base A. sanguineus Bagnall.

Acanthothrips albivittatus sp. nov.

Female.—Length about 2 . 1 mm. Dorsal surface roughened with
numerous microscopic tubercles; ventral surface smooth. General color

(reflected light) dull mahogany brown, with a narrow latero-dorsal white
stripe which originates at the posterior margin of the eye and terminates
in a small spot at base of segment 8 of abdomen ; on the head the stripe is

slightly narrower than the basal antennal segment; on the prothorax it

broadens posteriorly and includes an irregular reddish spot; at the an-
terior mesothoracic margin it is broken up into two subequal triangular
areas, from which it continues as a much narrower line to the base of the
abdomen ; it is lacking on the first abdominal segment, and extends un-
interruptedly from the second to the eighth. General color (trans-

mitted light) yellowish brown, with maroon-colored hypodermal pig-

mentation; legs blackish brown, non-pigmented, shaded laterally with
black; tarsi and inner surface of fore tibiae paler; antennae uniform black.

Head 1 .4 times as long as wide; cheeks converging abruptly to eyes
and to base of head; dorsal and lateral surfaces faintly reticulate, scarcely
visibly spinose and not roughened by spine-bearing tubercles

;
postocular

bristles long, pointed!- Eyes large, contained in length of head two and
two-thirds times, and wider than the interval between them. Ocelli

sub-approximate, opposite center of eyes. Antennae about one and
one-fourth times as long as head; segments 3-6 urn-shaped; 7 and 8

closely united, the latter conical; sense cones long, slender; segments
3, 5, and 6 each with one on either side of apex; 4 with an additional

*I have specimens of this species taken at Muncie and Urbana, Illinois.

tThese bristles are wanting in A. niagnafemoralis Hinds.



375

outer one; 7 with a sub-apical dorsal one. Mouth cone pointed, attain-
ing base of prostemum.

Prothorax two-thirds as long as head, and (including coxae) slightly

less than twice as wide as long; all usual spines present, blunt. Ptero-
thorax scarcely wider than prothorax; sides sub-parallel, slightly con-
cave. Wings long, without prominent longitudinal vein. Fore femora
five-eighths as wide as length of prothorax, and with a sub-apical acute
tooth; fore tarsi armed with a stout tooth.

Abdomen about as wide as prothorax. Tube about . 7 as long as
head; bristles at tip shorter than head.

Measurements:—Total length 2. 1 mm.; head, length .36 mm., width
.25 mm.; prothorax, length .24 mm., width (including coxae) .46 mm.;
pterothorax, width .46 mm.; abdomen, width .47 mm.; tube, length .25

mm., width at base .092 mm., at apex .059 mm. Antennae: 1, 45 fi;

2, 70,«;3, 118 /i; 4, 112//; 5, 100 /x; 6, 73//; 7, 67//; 8, 38//; total, .62 mm.

Described from one female taken on the trunk of a Carolina poplar

at Bloomington, Illinois, July 10, by Hugh Glasgow.

Genus Liothrips Uzel, 1895.

Liothrips ( ?) ocellatus sp. nov.

Female.—Length about 2.2 mm. General color black, excepting
tarsi and articulations of legs, which are slightly paler, and antennal seg-

ments 3-5, which are at least partly yellow.

Head 1.15 times as long as wide, widest just behind eyes, narrowing
evenly to base, where it is . 84 of the postocular width ; vertex elevated
between eyes, slightly overreaching insertion of antennae, and bearing the
anterior ocellus at its extremity ; lateral and dorsal surfaces transversely

striate, sparsely, briefly, and scarcely visibly spinose; postocular bristles

blunt, three-fifths as long as eyes. Eyes large, one-third as long as head.
Ocelli anterior; posterior ocelli opposite anterior third of eyes: anterior

ocellus overhanging. Antennae eight-segmented, twice as long as head;
segments 1 and 2 concolorous with body, excepting apex of 2, which is

paler apically; 3 uniform bright lemon-yellow; 4 yellow, dusky at base
and apex; 5 blackish brown, its second and third fifths brownish yellow;

segments 6-8 concolorous with body.*
Prothorax two-thirds as long as head, and (including coxae) 2.4

times as wide as long; all spines present, moderately long, blunt, the two
pairs near the posterior angles longest. Pterothorax slightly wider than
prothorax, about as long as broad, slightly narrower posteriorly; sides

convex, gently arcuate. Wings present, reaching about to base of tube;

fore wings brownish at base, not narrowed at middle, with three sub-

*I have not described the position of the sense-cones, as several of these are
apparently lacking.



376

basal brownish spines on anterior margin, and with the apical fringe on the

posterior margin double for fourteen hairs; posterior wings with a weak
median vein reaching about to middle. Legs stout, not long; fore tarsi

unarmed.
Abdomen large, slightly wider than pterothorax, tapering roundly

from segment 6 to base of tube. Tube about .8 as long as head, taper-

ing evenly from base to apex.

Measurements:—Total length 2.21 mm.; head, length .24 mm.,
width .21 mm.; prothorax, length .16 mm., width (including coxae) .38

mm.; pterothorax, width .42 mm.; abdomen, width .46 mm.; tube

length .20 mm., width at base .092 mm., at apex .042 mm. Antennae

1, 36 p.; 2, 62 //; 3, 81 /x; 4, 81 /x; 5, 73 /i; 6, 67 //; 7, 62 //.; 8, 35 pt; total

. 50 mm.

Described from a single female taken at Hillery, Illinois, in moss,

by C. A. Hart and James Zetek.

Genus Cryptothrips Uzel, 1895.

Cryptothrips carhonarius sp. nov. (Fig. 8).

Male.—Length about 2 . 22 mm.
(abdominal segments somewhat
telescoped). Color uniform coal-

black, excepting tarsi and articula-

tions of legs, which are dark black-

ish brown.
Head rectangular, about one

and one-half times as long as wide,

sides parallel; lateral and dorsal

surfaces faintly reticulate, set with
a number of short spines and a
longer pair at middle of dorsum;
vertex transverse

;
postocular spines

long, slender, pointed; spines just

behind ocelli about equal in length
to the postocular. Eyes moderately
large, not protruding, occupying
the anterior angles of head. Ocelli

moderately large, their diameter
about three times that of facets of

eyes ; anterior ocellus not overhang-
ing; posterior ocelli opposite cen-

ters of eyes and almost touching
their inner margins. Antennae eight -segmented, 1.4 times as long as
head, uniform black inj color; segments 3-6 sub-clavate; 7 fusiform,

Fig. 8

Cryptothrips carbonarius, male
prothorax; b, tube. (J. D. H., del.)

a, head and



377

pedicellate; 8 fusiform. Mouth cone somewhat wider than long, apex
broadlv rounded; tip of labrum just attaining tip of labium.

Prothorax about three-fifths as long as width of head, and (includ-

ing coxae) about three times as wide as long; usual spines all present, the
two pairs near the posterior angles much the longest; anterior mar-
ginals moderately long. Pterothorax about 1.4 times as wide as long,

somewhat broader than prothorax; sides nearly straight, slightly converg-
ing posteriorly ; anterior comers scarcely projecting beyond the general

outline. Wings present.* Legs nearly concolorous with the body;
anterior tarsi armed with a stout tooth. Abdomen moderately stout,

about as broad as pterothorax, widest at about segment 3, from which
it tapers evenly to segment 6, and then rather abruptly to base of tube.

Tube four-sevenths as long as head, widest at base, constricted just

before apex; intermediate portion parallel-sided, exactly three-fourths

the diameter of base; surface not spinose.

Measurements:—Total length 2.22 mm.; head, length .46 mm.,
width .30 mm.; prothorax, length . 17 mm., width (including coxae) .49

mm.; pterothorax, width .52 mm.; abdomen, width .62 mm.; tube,

length .27 mm., width at base . 104 mm., at apex .054 mm. Antennae:

1, 61 «; 2, 78 ,«; 3, 123 a; 4, 106 /y; 5, 97 /<; 6. 81 /«; 7, 57 /«; 8, 47 jx;

total .65 mm.

Described from a single macropterous male, taken at Pulaski, 111.,

May 21, 1907, in sweepings from grass and weeds, by Mr. C. A. Hart.

Genus Idolothrips Haliday, 1852.

Idolothrips flavipes sp. nov. (Fig. 9).

Female.—Length about 3.1 mm. Color of body coal black; all

tibiae and tarsi, and at least the basal portion of antennal segments 3 to

6, bright yellow.

Head ver}^ slightly more than twice as long as wide, narrower just be-

hind eyes and at base, widest across eyes; finely striated and set with

several stout spines; vertex conical, produced, apex overhanging inser-

tion of antennae ; anterior portion of head provided with a pair of promi-

nent bristles in addition to the postocular, situated on either side of the

prolonged vertex. Eyes large, finely faceted, prominent, bulging.

Ocelli small, their diameter about equal to that of facets of eyes; anterior

ocellus occupying extreme vertex; posterior ocelli slightly in front of

centers of eyes, and slightly removed from their inner margins. An-
tennae eight-segmented, slender, about 1.4 times as long as head; seg-

*The only specimen which I have of this species has been cleared in potassium
hydroxide, and the wings, as a consequence, are unfit for study.



378

ments 3-5 clavate; 6-8 fusiform; segments 1, 2, 7, 8, apical half of 6, and
apical fourth of 5, dark blackish brown; remainder of antenna lemon-

yellow, excepting apex of 4, which is

clouded with brown. Mouth cone about
as long as its width at base, broadly
rounded; tip of labrum just attaining tip

of labium.
Prothorax almost as long as width

of head, and (including coxae) slightly

more than twice as wide as long ; surface

finely reticulate; usual spines all present,

the two pairs near the posterior angles

somewhat longer than the others. Ptero-

thorax sub-rectangular, about two-thirds

as long aswide, and slightly broader than
prothorax; anterior corners projecting

slightly beyond the lateral margins.
Wings represented by small pads, which
are about equal in length to the head,

and four times as long as broad. All

tibiae and tarsi bright yellow, the former
often clouded with brown at base; re-

mainder of legs concolorous with body
anterior tarsi unarmed.

Abdomen broad, about one and one
half times as wide as pterothorax, widest

at segment 4, from which it tapers evenly

to tube, giving the abdomen a lanceolate form. Tube almost as long as

head, tapering evenly to middle, and then some what more abruptly to

apex; surface not spinose.

Measurements:—Total length 2.82-3 .34 mm.; head, length .53

mm., width .25 mm.; prothorax, length .21 mm., width (including

coxae) .46 mm.; pterothorax, width .48 mm.; abdomen, width .74 mm.;
tube, length .47 mm., width at base . 114 mm., at apex .052 mm. Ant-
enna: 1, 48 //; 2, 70 //; 3, 140 pt; 4, 120 /<; 5, 112 p.; 6, 92 p; 7, 67 //;

8, 70 ji; total, .72 mm.
Male.—Smaller than female (total length 2.58-2.97 mm.). An-

terior femora no stouter than in female; fore tibiae provided with a stout

tooth. Abdomen slender, tapering evenly from almost the very base.

Described from several males and females, all from Illinois, as

follows: Dubois, Apr. 28 (C. A. Hart and L. M. Smith); Homer,
Mar. 30, Apr. 17 (C. A. Hart, J. D. H.) ; "N. 111." (A. Bolter). All

specimens were taken among fallen oak leaves.

Fig. 9

Idolothrips flavipes, female, head and pro
thorax. (J. D. H., del.)



SYSTEMATIC LIST OF SPECIES.

1

.

Heterothrips ariscemcB gen. et sp. nov 362

2. Sericothrips pulchellus sp. nov 363

3. Zygothrips longiceps sp. nov 364

4. Lissothrips muscorum gen. et sp. nov 365

5. Trichothrips americamis sp. nov 366

6. " angusiiceps sp. nov 367

7.
' " longitubus sp. nov 368

8. " btiffcB sp. nov 369

9. Plecirothrips antennatus gen. et sp. nov 370

10. Neothrips corticis gen. et sp. nov 372

1 1

.

Allothrips megacephalus gen. et sp. nov 373

12. Acanthothrips albivittatus sp. nov 374

13. Liothrips (?) ocellatus sp. nov 375

14. Cryptothrips carbonarms sp. nov 376

15. Idolothrips flavipes sp. nov 377

Issued August 22, 1908.

379