560 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.40. 



tooth longer, maxillary palpi 6-jointed, labial palpi 4-jointed, palpi 

 long, slender; antennae inserted at the top of the clypens and almost 

 against the orbits, the distance between them almost as great as 

 the width of eyes at clypeus; abdomen, thorax, legs, and wings 

 much as in Stigmus. 



The lower posterior margin of the head is strongly angled in the 

 genotype, but this may only be a specific character. 



Type. — Gonostigmus typicus Rohwer. 



Gonostigmus may at once be separated from Stigmus by the head 

 being longer than wide, the facial quadrangle being narrowed below, 

 the larger and produced clypeus, the antennae inserted very close to 

 the orbits. 



GONOSTIGMUS TYPICUS, new species. 



Female. — Length 3 mm., slender. Lower inner orbital margins 

 finely foveolate ; head strongly angled on the lower posterior margin ; 

 the posterior margin finely carinate; front finely granular, the rest 

 of the head shining and impunctate; ocellar line at least as long as 

 the ocellocular line; flagellum simple, the first and second joints equal 

 in length; pronotum strongly ridged and sharply angled laterally; 

 dorsulum very finely longitudinally scratched; scuto-dorso suture 

 strongly foveolate; propleurse strongly longitudinally striate; a longi- 

 tudinal suture on the rnesopleurse, the area above which is finely 

 striate-granular, the area below finely striate; propodeum dorsally 

 with large reticulations, laterally longitudinally striate; legs without 

 spines; petiole slightly longer than the hind femora, with five fine 

 carina on the dorsal and lateral surfaces; abdomen normal. Black, 

 shining; mandibles, scape, two joints of flagel, tubercles, tegulse,' 

 four anterior legs, posterior trochanters and tarsi pale yellow. The 

 usual pubescence sparse; wings clear hyaline, iridescent; venation 

 and stigma dark brown, nervures paler toward the base of the wings. 



Motzorongo, Vera Cruz, Mexico. One female collected February 

 11, 1892, by H. Osborn. 



Type.— Cat. No. 13738, U.S.N.M. 



Genus DIODONTUS (Curtis) Shuckard. 



DIODONTUS BIDENTATUS, new species. 



This may be the undescribed male of Diodontus adamsi Titus, but 

 the description of that species is very brief, and the following species 

 differs in being 3 mm. smaller and having the tubercles pale. It is 

 easily distinguished from the other described Nearctic species by the 

 dentate clypeus. 



Male. — Length 3.5 mm. Labrum concealed; clypeus produced in 

 the middle, with two large, obtuse teeth, the emargination between 



