September, 1942 IFRISON: 
3A 2A 
Fig. 115.—Hastaperla brevis. 
eae WINGS 
SS 
Fig. 116.—Chloroperla terna. 
margin of pronotum is at least twice 
as great as diameter of eye. .Kathroperla 
Head shorter than in Kathroperla, but 
slightly longer than pronotum; com- 
pound eyes situated on sides of head 
about their diameter from front mar- 
PLOTS DEONORUIIS > tik 4); bos te ene 3 
3. Third anal vein of forewing not present 
or, if present, not fused with second 
anal vein so that second anal vein ap- 
pears branched, fig. 116...... Chloroperla 
Third anal vein of forewing with basal 
portion fused with second anal vein so 
that second anal vein appears branched, 
figs. 117-118 
4. Anal lobe of hindwing small, in length 
extending about to middle point of 
wing, fig. 117; small, pale-colored spe- 
Elias i 2 ol ee ie ee tes Alloperla 
Anal lobe of hindwing large, in length 
extending well beyond middle point of 
wing, fig. 118; medium-sized, dark- 
eolorea mspecies. 5. 210 b45., 2 Paraperla 
In The Stoneflies, or Plecoptera, of Illi- 
nois (Frison 1935a), the generic key -for 
Chloroperlidae included the genera Hasta- 
perla (= Chloroperla of North American 
authors) and Isoperla. Isoperla was in- 
included in the key on the basis of actual 
records of numerous species from Illinois. 
Hastaperla was included because of the 
occurrence of the species brevis (Banks) 
(— cydippe of North American authors) 
in Indiana at a locality a few miles from 
NortH AMERICAN PLECOPTERA 
RIGHT WINGS 
RIGHT WINGS 
Fig. 117.—Alloperla caudata. 
RIGHT WINGS 
Fig. 118.—Paraperla frontalis. 
the Illinois boundary line, and also be- 
cause of the probability of its eventual 
capture in Illinois. In a later article 
(Frison 1937), giving additions to the 
Illinois stonefly faunal list, no new records 
of Chloroperlidae for Illinois were avail- 
able, but a new species of Hastaperla was 
described from Wisconsin as Chloroperla 
orpha. 
Since 1937, continued field work in 
Illinois in restricted local habitats has re- 
vealed actual Illinois material of the 
genera Hastaperla and Alloperla. Records 
of the Illinois specimens of Alloperla 
caudata Frison, dA. banksi Frison and 
FHlastaperla brevis (Banks) are given 
under my notes and descriptions of these 
species in following pages. 
Chloroperla terna new species 
MaAe.—Head, thorax, abdomen, cerci, 
basal segments of antennae and most of 
legs dominantly a pale yellowish green; 
apical segments of antennae fuscous; local- 
ized black or fuscous markings on thorax 
and abdomen. Ocelli and compound eyes 
black. No gill remnants. 
Head slightly wider through compound 
