September, 1942 
1937 which led to additional collections 
of nymphs in 1938 and the rearing of the 
adults. The adults of signata are much 
larger than those of this new species and 
the body integument js heavily suffused 
with brown, whereas in this new species 
the body integument is very pale colored. 
The apical segments of the anal Cerciein 
the adults of signata are much longer than 
comparable segments of this new species. 
Isoperla slossonae (Banks) 
Perla slossonae Banks (1911, p. 335). Orig- 
inal description, Cates 
Clioperla annecta Needham & Claassen 
(1925, p. 140). Original description, 2. New 
synonymy. 
Studies of the single female type of 
slossonae in the collection of the Museum 
NY MPHAL 
MAXILLA 
NymMPHAL Lasium 
Fig. 106.—IJsoperla slossonae. 
of Comparative Zoology (Type No. Il,- 
m2/), and the typic female series of an- 
necta, in the collection of Cornell Unij- 
versity, have revealed that these specimens 
are of the same species and hence the more 
recent name of annecta falls in synonymy. 
For the sake of exactness in record, it may 
be stated that the type of slossonae js some- 
What darker in coloration than the typic 
series of annecta and most specimens in 
Frison: Norri AMERICAN PLECOPTERA 329 
the Illinois Natural History Survey col- 
lection, but such a difference in degree 
of coloring often occurs in stonefly species. 
The original description of slossonae 
mentions both the male and female, but 
only a single female type is now in the 
collection at Cambridge. The original de- 
scription of annecta is based upon females 
only, collected in New York and Quebec. 
Since neither Banks (1911) or Need- 
ham & Claassen (1925) have figured the 
male or described certain important char- 
acters useful in identifying it, I present 
the following brief description of certain 
structures. 
Mae.—Agrees in general with de- 
scription of annecta as given for female 
by Needham & Claassen (1925 eee: 
portant structural differences are as fol- 
lows: Subanal lobes developed into prom- 
inent sturdy hooks; ninth abdominal ster- 
nite much produced, fig. 106; eighth ab- 
dominal sternite with a broad, shallow 
lobe on posterior margin, fig. 106. Very 
Suggestive of and closely related to pinta 
Frison (1937). 
As a result of field work in several 
states, which enabled me to rear males 
and females from nymphs, I am now able 
to present the following description of the 
nymph. 
NympxH.—General color pale yellow- 
ish, with darker areas on dorsum of head, 
thorax and abdomen, as in fig. 107. An- 
tennae, legs and anal cerci mostly yellow- 
ish, with dark bands at apex of femur and 
base of tibia especially prominent. 
Head with three ocelli forming an al- 
most equilateral triangle, each lateral ocel- 
lus about as far apart as each is distant 
from inner edge of compound eye; no 
occipital ridge; basal segments of mouth- 
parts but slightly extending out from sides 
of head. Labium and maxillae as in fig. 
106. 
Pronotum much broader than long, 
with markings as in fig. 107, corners very 
much rounded. 
Abdominal tergites with a general dark 
brown to black background, with rows of 
light spots, fig. 107, posterior margin of 
tenth or last tergite yellowish. Cerci long, 
many segmented, segments progressively 
longer from base to apex; a longitudinal 
row of long, fine setae on apical segments 
in addition to smaller, spinelike ones en- 
circling apex of each segment. 
