58 
as third; stigma robust, rounded on lower margin; sheath not very 
robust, rounded at apex, and with rather long and dense hairs; cerci 
long, slender, as long as or longer than third cubital cross vein; claws 
deeply cleft, rays nearly equal. Color of head, thorax, base of first 
dorsal sclerite, sheath, extreme tips of posterior femora, apical half— 
sharply defined—of posterior tibiv, and their tarsi black; sometimes 
the dorsal middle of segments 2 to 4 and rarely 6 and the cerci brown- 
ish black; bases of antenne, tips of clypeus, and the labrum, palpi, 
outer angles of pronotum, tegulie, legs, and abdomen yellowish ferru- 
ginous; posterior femora and abdomen darker; veins and stigma 
brown; costa yellowish. 
Four females, Cresson’s types, Pennsylvania (Coll. Am. Ent. Soe.), 
and seven females bred from larve on alder, Cadet, Mo., October 5, 1854 
(Coll. U. S. Nat. Mus.). Adults emerged during latter part of March 
and early in April. The last larval stages and the cocoon are described 
by Mr. H. G. Dyar, who states that the larve are gregarious edge 
feeders on alder. 
20. Pteronus dyari new species. 
Female.—Length 6 mm.; very robust; clypeus nearly truncate; ocel- 
lar basin well defined, with prominent anterior angle; antennal fovea 
very shallow, indistinct; head and thorax coarsely punctured; anten- 
ne but little shorter than the body, tapering, third joint longest; vena- 
tion normal; stigma stout, regularly rounded on lower margin; sheath 
short, stout, scarcely projecting; claws deeply notched, rays subequal. 
Color black, shining; mouth parts strongly infuscated; angles of pro- 
notum, tegule, first to fifth segments of abdomen ventrally and dorsally, 
yellowish ferruginous; cox except bases, trochanters, basal half of 
posterior tibiz, whitish; anterior tibiwe and tarsi and anterior and pos- 
terior faces of anterior femora, together with bases of middle pair, pal- 
lid; wings nearly hyaline, or very slightly infuscated; veins, including 
stigma and costa to base, very dark brown. 
Male.—Length 5.5 mm.; structurally as in female; procidentia long, 
projecting; antennz more robust, tapering. Color as in female, except 
that the abdomen is wholly black and the legs are yellowish, except 
extreme tips of posterior femora and apical half of posterior tibie and 
their tarsi. 
One female and one male. H.G. Dyar, cdllector, New York. (Coll. 
Dyar.) 
21. Pteronus fulvicrus Provancher. 
1882. Nematus fulvicrus Provancher. Nat. Can., XIII, p. 291. 
1883. Nematus fulvicrus Provancher. Faun. Ent. Can. Hym., p. 740. 
1890. Nematus salicis Ashmead. Bull. Colo. Biol. Assn., 1, p. 15. 
1894. Nematus salicicola Dalla Torre. Cat. Hym., I, p. 257. ‘ 
Female.—Length 8.5 mm.; robust; clypeus broadly but not very 
deeply notched; walls about ocellar basin distinctly defined; crest 
