286 E. T. CRESSON, JR. 



nearly as broad as fifth and much longer, not cleft ; inter- 

 mediate lobe fully visible at sides ; ventral lobe small and 

 brown ; legs rather slender with weak spines ; apical and 

 basal joints of post-tarsi in proportion 1:3; wings short with 

 colored stigma. 



This species is at once distinguished by the nearly shining 

 indistinctly marked abdomen, the large globose hypopy- 

 gium and short ovipositor. There is a male in the collection 

 here without data, except label marked "Sept." It is very 

 pale and much bleached, the legs almost entirely yellow. 



5. P. flavitarsis Williston. 



cf. Front and face silvery ; antennae black ; third joint acute, yel- 

 low. Mesonotum and scutellum brownish ; pleura grayish. Abdomen 

 blackish-brown, subopake ; first segment and apices of following 

 opake gray. Legs black ; extreme apices of femora, greater part of 

 tibiae and tarsi, yellow; femora not markedly thickened. Wings nearly 

 hyaline ; stigma yellow. Length 4.0 mm. 



Described from Mexico. The description is too short to 

 be of much value, but it seems to place the species very 

 close to nigricornis Adams. 



6. P. nigricornis Adams. 



d 1 . Front and face silvery; antennae black, with third joint short 

 acuminate. Mesonotum brownish ; pleura and metanotum silvery 

 pollinose; scutellum subopake; halteres black. Abdomen black, 

 subopake ; apex of first, interrupted apices, dilating laterally, of 2-4, 

 and broad apex of fifth, white. Hypopygium black, cleft. Femora, 

 except bases and apices, black; tibiae, except median ring, yellow; 

 inner surface of post-femora polished. Wings hyaline ; stigma fuscous. 

 Length, 4.2 mm. ; wings, 5.0 mm. 



Described from Missouri. The species is unknown to me, 

 but seems to be allied to the following. In the table of 

 species I assume that the humeri are black. 



7. P. alternatus n. sp. 



c? . Front brownish or grayish ; face silvery ; antennas brownish- 

 black, with third joint broadly acute (Fig. 18). Mesonotum bare, 

 opake brown ; lateral and broad anterior margins cinereous, with rudi- 

 ments of a pair of median brown vittae. Scutellum opake-brown; pleurae 

 and metanotum cinereous ; halteres and humeri brown or blackish. 

 Abdomen opake, with bases of all segments velvety-brown ; apices 

 and broad lateral angles cinereous and more shining ; segments 2-4 

 subequal and fifth as long as third and fourth together. Hypopygium 



