558 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.40. 



dorsal aspect of propodeum with a transversely ridged enclosure, 

 parted by a longitudinal carina, in outline the inclosure is somewhat 

 like a truncate arrowhead; sides of propodeum reticulate; second 

 cubital cell slightly narrowed above; sides of petiole with strong 

 oblique carina? apically, in length subequal with the posterior femora; 

 pygidium well denned, narrow, about one and a half times as long 

 as wide. Shining black; spot on mandibles and tubercles tegula? 

 and posterior tarsi ferruginous ; anterior femora and posterior tibia? 

 brownish; venation brown, stigma black. 



Highspire, Pennsylvania. One female collected by Mr. W. S. 

 Fisher, June 13, 1908; two other females collected near Harrisburg, 

 Pennsylvania, June 14, 1909, by A. B. Champlain, and July 18, 1909, 

 by Mr. P. R. Myers; also a female from the Baker collection from 

 Pennsylvania. 



Type.— Cat. No. 13769, U.S.N.M. 



STIGMUS APHIDIPERDA, new species. 



Of the described nearctic species this is more closely allied to 

 S. fraternus Say, from which it may be known by the dorsal lateral 

 angle of the pronotum (not the sides) being dentate, the apical joint 

 of the antennae not spatulate and other minor characters. 



Female. — Length 4 mm. Process of the clypeus slightly emar- 

 ginate; frontal impressed line strong; pedicellum and third antennal 

 joint subequal in length, third joint longer than the fourth; ocelloc- 

 cipital line about twice as long as the postocellar line; mesonotum 

 finely punctured; dorsal aspect of propodeum with a trapazoidal- 

 shaped enclosure bounded laterally by rectangular-shaped reticula- 

 tions; posterior part of sides of propodeum granular; petiole shorter 

 than the hind femora, obliquely striate; pygidium short, not twice 

 as long as wide, narrow. Black; mandibles, scape in front, four 

 anterior tibiae and tarsi, posterior tarsi and tegula? dark ferruginous; 

 tubercles white; wings hyaline, irridescent; venation and stigma 

 black. 



The intermediate tibia? may be mostly black. 



Male. — Length 4 mm. Bears about the same relation to the female 

 as does the male of fraternus to its female. Anterior margin of the 

 clypeus somewhat produced; head dulled with fine granulation, 

 frontal impressed line strong; antenna? rather slender, third and 

 fourth joints subequal, the apical joint pointed; mesonotum finely 

 granular; scutellum somewhat impressed; sutures of the mesopleura? 

 not as strongly foveolate as in female; sculpture of propodeum 

 similar to the female, but the enclosure is not narrowed anteriorly. 

 Differs from the female in coloration in the black flagellum, and 

 nearly black intermediate tibia?. 



