PLECOPTERA NYMPHS OF NORTH AMERICA — 35 
femora and tibiae fringed with hairs, first segment of tarsus 
about twice as long as second, third segment about twice as long 
as one and two combined; two large tarsal claws. 
Abdomen cylindric, segments smooth, tenth segment narrow 
below, and above produced into a triangular pointed conical 
process in both male and female; cerei nearly as long as ab- 
domen, composed of thirty or more segments in the mature 
nymph, somewhat hairy and each segment with a whorl of short 
spines at the distal end. 
In the mature nymph we find seventeen pairs of tufted gills 
which are located as follows: three pairs in the cervical region ; 
a small pair on the antero-lateral margin of the front legs; four 
pairs encireling the body just posteriorly to the front pair of 
legs; one pair between the mesothoracic legs; three pairs located 
back of the base of the mesothoracie legs; one pair between base 
of the metathoracic legs; one pair on the postero-lateral margin 
of the metathoracie legs and one pair on each of the first three 
abdominal segments. 
This genus occurs only in the Western States. Pteronarcella 
badva was reared by Dr. J. G. Needham from nymphs collected 
in Logan River, Logan, Utah, the adults emerging June 23, 1926. 
These are the only rearing records of the genus, but fortunately 
mature nymphs in which the adult genital characters could be 
distinguished have enabled me to identify also the immature 
stages of Pt. regularis. 
The nymphs are herbivorous, and from their body form and 
general structure, I would infer that they generally inhabit the 
smaller spring brooks where much dead and decaying vegetable 
matter accumulates. 
Key to the Nymphs of Pteronarcella 
1. Filaments of gill tufts long; at least twice as long as the 
basal conical process of gill tufts..... badia Hagen (p. 35) 
Filaments of gill tufts short; less than twice as long as bases 
gf) 3OO" 1 ARTA gad ee ae regularts Hagen (p. 36) 
Pteronarcella badia Hagen 
(Plate 2, figs. 22-26; plate 12, figs. 177-178; plate 13, fig. 185.) 
Length of body up to 21 mm.; antennae up to 9 mm.; cerci 
up to 9 mm. 
Color almost uniformly brown but often with lighter markings 
on the abdomen. 
Head much narrower than pronotum, brown, sometimes with 
