450 
NORTH AMERICAN PLECOPTERA 
Adult 
d^. — Length to tip of wings, 33 to 40 mm.; expanse of wings, 58 to 66 mm. 
9 . — Length to tip of wings, 41 to 46 mm.; expanse of wings, 72 to 84 mm. 
Head and thorax dark fuscous above, paler beneath, abdomen paler. Head 
as wide as prothorax, spots beyond the lateral ocelli, rufous; supra-antennal 
plate ending in a sharp tooth. Pronotum nearly as long as broad, anterior 
border and sides straight, posterior border convex, angles not conspicuously 
sharpened, median reddish-yellow line broader at ends. Legs dark fuscous. 
Male. The ninth ventral segment not produced, with a hollowed scar each 
side, the middle area broader at the base than the tip. The tenth segment 
very narrow below; bifid above, the lobes, erect, transverse knobs. The 
sub-anal plates broadly triangular. The supra-anal plate modified as a sperm- 
conveyer, above it appears as a flat trough, cleft at the tip, on the ventral side 
it is elongated before the cleft, and ends in a sperm cup (fig. 5). 
Female. The eighth ventral segment produced before the tip into two flat, 
tooth-like, or somewhat triangular, processes, oblique outside, and straight 
inside, reaching half way across the ninth segment, separated by a rounded 
notch (fig. 6). 
We hav^e six males; two from Colorado, VI, 30, 1904, and 
four (alcoholic) with no locality labels; and six females, two 
from Colorado, 1904; one from Los Pinos, Colorado, one from 
California and two (one alcoholic) without locality labels. 
Nymph 
Length of body, 34 mm.; length of antennae, 17 mm.; length of setae, 8 mm. 
Antennae unicolorous, of about seventy segments; the supra-antennal plate 
ending in a sharp tooth. Prothorax broader posteriorly; its front and hind 
margins convex, each angle produced laterally in a long, up-curved tooth, 
making the sides appear concave (fig. 19). 
In the male the supra-anal plate, less tapering, and bent ventralward (fig. 
22). In the female the tenth tergite narrow, prolonged in a sharp, median, 
conical process, the supra-anal plate (fig. 23). Setae of uniform coloration, 
stout, a little over a fourth the length of the body. 
Described from cast skins in which no color pattern was visible. 
Exuviae from Platte Canyon, Colorado; Powder River, Colo- 
rado; VI, 15, 1883; Pecos, New Alexico; VI, 7, 1903; and imma- 
ture nymphs from Ogden, Utah. 
Pteronarcys princeps Banks 
Adult 
1907. Pteronarcys princeps Banks, Can. Ent., 39: 327. 
1907. Pteronarcys fumipennis Klapdlek, Bull. Internal. Acad. Sci. Boh6me, 
12, p. 11 of reprint. 
