30 THOMAS SAY FOUNDATION 
Pteronarcys biloba Newm. 
(Plate 2, figs. 17-21; plate 11, figs. 171-172; plate 34, fig. 232; plate 35, 
figs. 235-236.) 
Length of body up to 40 mm.; antennae up to 16 mm.; cerci 
up to 12 mm. 
General color, chocolate brown to blackish, sometimes with in- 
distinet lighter longitudinal stripes upon the abdomen; in living 
nymphs, orange markings on the lateral margins of the pronotum, 
and a yellowish orange band on the middle portion of the an- 
tennae and cerci, which fades to pale yellow in alcoholic speci- 
mens. 
Head much narrower than prothorax; uniformly brown except 
for the somewhat lighter smooth rounded marks each side of the 
ocellar triangle, and usually with a lighter median area near the 
posterior margin of the occiput, which possesses numerous longi- 
tudinal rugosities; antennae of sixty or more segments, blackish, 
but with a yellow band covering four to ten segments, just be- 
yond the middle, and lighter toward the tip. 
Pronotum almost twice as broad as long, widened posteriorly, 
front angles considerably produced, hind angles sub-acute; 
front margin somewhat concave, hind margin sinuate; dise of 
pronotum with coarse but not very deep rugosities; dark brown 
with lighter margins. 
Legs brown with tips of the femora and the tarsi lighter, also 
a narrow lighter longitudinal line on the femora; the femur, tibia, 
and tarsus fringed with hairs. 
Abdomen cylindric, dark brown with lighter markings; ab- 
dominal segments one to eight with large lateral apical hooks 
directed outward from the body. Although these hooks become 
shorter posteriorly, they are very pronounced on the eighth seg- 
ment; segments nine and ten of abdomen smooth; tenth tergite 
much produced. Cerei of about forty segments, dark brown, with 
a yellow band beyond the middle, and sometimes with the tip 
lighter. 
Many nymphs from: Ithaca, N.Y.; Oneida Co., N.Y.; Tarbel, 
N.Y.; Allegany Co., N.Y.; Old Forge, N.Y.; Moffitsville, N.Y-.; 
Osgood R., Adirondack Mts., N.Y.; Ammanoosie R., W. Milan, 
N.H. 
Pteronarcys proteus Newm. 
(Plate 1, figs. 11-16; plate 11, figs. 169-170; plate 34, fig. 234; plate 35, 
fig. 237.) 
Length of body up to 40 mm.; antennae up to 21 mm.; ecerci 
up to 7 or 8 mm. 
