LUCY WRIGHT SMITH 
437 
Ny7nphs 
The nymphs of this sub-family are perhaps more distinct than 
the adults. Their bodies are much more cylindrical than those 
of any of the other members of the group and their coloration is 
striking. They are a uniform chocolate brown with conspicuous 
tufts of bushy, white, tracheal gills on the venter. 
PTERONARCYS Newman 
1838. Pteronarcys Newman, Ent. Mag., 5: 175. 
1842. Pteronarcys Pictet, Perlides, p. 125. 
1842. Pteronarcys Rambur, Hist. Nat. Ins. Neur., p. 449. 
1861. Pteronarcys Hagen, Syn. Neur. N. A., p. 14. 
1876. Pteronarcys Provancher, Le Nat. Can., 8: 188. 
1877. Pteronarcys Hagen, Stett. Ent. Zeit., 38:477. 
1883. Pteronarcys Provancher, Pet. Faun. Can. N4urop., p. 67. 
1906. Pteronarcys Banks, Proc. Ent. Soc. Wash., 8: 8. 
1907. Pteronarcys Klapdlek, Bull, intemat. Acad. Sci. Boh^me, 12, page 1 
of reprint. 
Adult 
This genus contains the largest stone-flies of the entire order. 
They are dark brown insects with strong, elongated bodies; rather 
triangular heads; long, slender antennae; short, stout setae; and 
large wings, heavily net-veined (fig. 9). 
Dark fuscous, with varied markings of paler colors, rufous, 
orange and 3 '^ellow. Head with prominent rounded eyes; three 
ocelli forming an equilateral triangle; outside the lateral ocelli 
conspicuous round spots of a paler color, or dark and shining; 
supra-antennal plate well developed; antennae long, and tapering. 
Prothorax wider than long, a little broader posteriorly^ sides 
and front about straight, hind margin convex, angles sharp, a 
more or less prominent median yellow line, embossed markings 
on the disc. The distal end of the femur with a triangular notch 
on the inner surface; the segments of the tarsi of unequal length, 
the first segment twice as long as the second, which is the short- 
est, and the third a little longer than one plus two. The remains 
of thirteen pairs of tufted gills carried over from those of the 
nymph, but small, shrivelled and inconspicuous. Wings large, 
somewhat clouded on the veins, venation reticulate. 
Abdomen cylindric, setae dark brown, paler at base. The 
instability of the color markings in this genus is so great as to 
TRANS. AM. ENT. SOC., XLIII. 
