FEMALES 
Gill remnants in cervical region; eighth ab- 
dominal sternite forming a shelflike plate 
that is distinctly indented in middle and 
that protrudes from under the backward 
projecting posterior margin of seventh 
SE venosa 
Without gill remnants in cervical region; 
eighth abdominal sternite not with small 
lobes on posterior margin showing under 
backward protruding posterior margin of 
seventh sternite, fig. 27... .trispinosa, p. 261 
A, 
as == 
SS a8 = 
OMINAL TERGITES 
Asi 
om 5 ABDOMINAL 
Itt SEGMENTS 
A\\huy 
=" 
= 
=== 
— 
aN 
ZA 
—————————— SSS 
—— 
— > 
—— 
= 
SaaS 
==— 
== 
— 
————— 
—— 
Fig. 26—Nemoura venosa. 
NYMPHS 
Gills in cervical region (Frison 1935a, fig. 
MEO el venosa 
Without gills in cervical Fezion, fig.°27.. > 
Se trispinosa, p. 261 
Nemoura trispinosa Claassen 
Nemoura trispinosa Claassen (19235 pe 289). 
Original description, ¢, Q. 
This species was originally described 
from New York specimens and_ subse- 
quently recorded by Needham & Claassen 
(1925) from Quebec. 
_ The finding of this species in a small, 
isolated relic habitat in northern Illinois, 
the same locality which produced the in- 
teresting record for Leuctra tenuis ( Pie- 
tee) adds a second species of Nemoura 
to the Illinois list. It is desirable, there- 
ere, to present an illustration, fig. 27, of 
the important characters used for identify- 
ing the sexes. 
New records for this species are as follows. 
| September, 1942 Frison: Norru AMERICAN PLECOPTERA 261 
2 ABDOMINAL STERNITES 
NYMPHAL HEAD AND 
PROSTERNUM 
| : 
aes 
i 
| my 
hi “af | 
A - SURFACE is B 
SUPRA-ANAL PROCESS 
= 
== 
= 
=< 
a 
ZN 
I) 
‘\ 
NAA 
oy LAN AY a 
ABDOMINAL ti v eZ 
SEGMENTS it SZ 
S——S 
oe ———— 
= 
wy } 
Hail ivy Hn 
OTK SS aay 
Ahh 
Fig. 27—Nemoura trispinosa. 
ILLINOIS.—ELGIN, Botanical Gardens: June 
1350193971) He rison & He Ross, 4¢, 109, 
13 nymphs; May 9, 1939, H. H. Ross & B. D. 
Burks, 17 nymphs. 
New York.—Essex County, Artists Brook: 
June 23, 1940, H. Dietrich, 1. 
Nemoura californica Claassen 
Nemoura californica Claassen (1923, op. 
284). Original description, 3, 2. 
Nemoura lobata Frison (1936, p. 260). 
Original description, ¢. New synonymy. 
When lobata was described by me in 
1936, I mentioned that it was "yery sug- 
gestive of N. californica Claassen.” Since 
then I have seen additional western ma- 
terial and during a recent visit to the 
California Academy of Sciences had the 
