PLECOPTERA NYMPHS OF NORTH AMERICA = 33 
suddenly turned down, with a sharp tooth at the tip, directed 
caudad; on each side near the base of the tenth tergite a swol- 
len area; ninth sternite not at all produced. 
Pecos, N. Mex.; Yellowstone R., Yellowstone Nat’l. Park; 
Weber R., Utah; Redwood Creek, Humboldt Co., Calif.; Poudre 
Canon, Col.; Boseman, Mont.; Ogden, Utah; Logan R., Utah; 
Voleano Creek, Calif. 
Pteronarcys princeps Banks 
(Plate 35, fig. 238.) 
Length of body up to 38 mm.; antennae up to 16 mm.; cerci 
up to 11 mm. 
General color dark brown, sometimes with a few lighter spots 
on the abdominal segments. 
Head much narrower than pronotum; surface somewhat ru- 
gose; brown except the frontal M-line, the lateral rounded marks, 
and the line along the elypeal-labral area, all of which are yellow- 
ish. 
Antennae uniformly brown, and composed of about sixty seg- 
ments. Antennal plates low and inconspicuous. 
Pronotum much wider than long, a little widened posteriorly ; 
all angles produced into short blunt processes, the front ones 
being directed outward and the hind ones rearward; surface ru- 
gose. Wing pads broadly rounded. Abdomen cylindric; brown, 
but in some specimens with small lighter dots on the tergites. 
Cerci brown, somewhat lighter toward the tip, and containing 
about forty segments. 
The sexes are readily recognized, and in the structural char- 
acters of the abdomen, the nymphs are very similar to Pt. cali- 
fornica, but they are readily distinguished from californica by 
the more bluntly pointed wing pads, the shorter prothoracic 
processes, and the blunt supra-antennal tubercles. 
Seemann (51) records this species from California, and states 
that she collected one adult and numerous nymphs. The adult 
male was determined by Dr. Needham as Pt. princeps, and Mrs. 
Seemann assumed the nymphs to be of the same species. I have 
the nymphs which she collected in Andreas Canyon, Cal., and 
the above description has been made from these specimens. In- 
asmuch as princeps and californica are very closely related, 
and inasmuch as these nymphs are very similar to those of cal- 
formca and yet show specific differences, I feel quite certain that 
the identification is correct. 
