90 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.63. 



anteriorly and posteriorly, the sides oblique; median area longer than 

 wide, not distinctly margined laterally, with a median carina; second 

 tergite more than twice as wide apically as basally, the sides straight 

 except near the apex; basal foveae shallow, strongly striate, the 

 striae reaching to the middle of the segment; median area broad, 

 elevated anteriorly, with several short carinae; following segments 

 short, broadly transverse, united a little less than half the length of 

 the second; wings broad, hyaline, extending half the length of the 

 second tergite past the apex of the abdomen. Dark brown; antennae 

 the color of the abdomen; legs lighter brov/n; tarsi touched with 

 yellow. 



Type locality. — St. Louis, Missouri. 



Type.— C&t. No. 2299, U.S.N.M. 



Redescribed from the two male types. Both were reared from the 

 Tenthredinid gall Euura s. -nodus Walsh. Ashmead says in the orig- 

 inal description, ''The species is unquestionably parasitic on inquili- 

 nous Cecidomyious flies known to inhabit this gall, and not on the 

 Tenthredinid." 



55. PLATYGASTER LONGIVENTRIS (Ashmead). 



Isocybus longiventris AsHiiE AD, Can. Ent., vol. 19, 1887, p. 130. — Cresson, Syn 

 of Hym.,1887, p. 249.— Ashmead, Bull, 44, U. S. Nat. Mus., 1893, p. 330. 



Female. — Length 1.2 mm. Head very thick and broad, wider than 

 the thorax, twice as wide as long through the middle, strongly con- 

 vex anteriorly and deeply emarginate posteriorly; cheeks convex; 

 occiput and cheeks behind finely aciculate; vertex and most of frons 

 highly polished; frons below finely diagonally aciculate; antennae 

 rather short, stout; joints seven to nine a little longer than wide, 

 thick ; ten as long as three and four united, oval, broadly rounded apic- 

 ally; thorax twice as long as wide, not very strongly convex 

 above; pronotum aciculate anteriorly on the sides; mesonotum 

 polished; notauli indicated by two short lines not more than 

 half as long as the scutellum; scutellum circular, evenly convex, 

 highly polished, without pubescence, first and second tergites 

 without pubescence; abdomen stongly flattened above and below, 

 subconvex on second sternite, as wide as the thorax; length of 

 abdomen to that of head and thorax united as four is to three; 

 first tergite about twice as wide as long, evenly rounded 

 above, with regularly placed carinae, the median area not defined, 

 foveae on second tergite narrow, with a few faint striae extending a 

 little beyond their apices; area between the foveae broad, unsculp- 

 tured ; segments beyond the second polished ; wings liyaline, extend- 

 ing to the apex of the first tergite. Reddish brown; legs and anten- 

 nae (except club which is brown) bright yellow. 



Type locality. — Jacksonville, Florida. 



Type.—Csit. No. 24609, U.S.N.M. 



