AMERICAN DIPTERA. 305 



tibiae and basal joints of tarsi yellow ; only inner surfaces of post- 

 femora polished ; femoral spines distinct ; posterior surface of middle 

 femora with more or less developed series of yellowish hairs ; apical 

 and basal post-tarsal joints in proportion of 1 : 2. Wings hyaline (Fig. 

 162). Length, 3.5 to 4.0 mm. 



28. P. angus n. sp. 



9 . Similar to sororius but smaller. Front broader than face, 

 shining, but silvery below; antennae black, long acute, or short acu- 

 minate. Ovipositor short, stout, abruptly terminating, and equalling 

 its large subglobose base (Figs. 94-95). Legs dark, similar to those 

 of alpinus. Length, 3.5 mm. ; wings, 5.5 mm. 



Type.— Cloudcroft, N. M., June 20, '02 ( Viereck, A. N. S.). 

 Type No. 5033. 



A specimen from St. Johnsbury, Vt., June (Figs. 95, 172, 

 Johnson, B. S. N. H.), seems to be very near this species, 

 but is larger (4.0 mm.) and front entirely cinereous (antennae 

 wanting). More material is wanting to fix this species more 

 clearly, but the stout ovipositor with its large base is very 

 different from the other allied forms. The broad shining 

 front of the typical specimen is also very characteristic. 



29. P. sororius n. sp. 



9 . Front and face silvery, only the ocellar region shining ; occiput 

 cinereous. Antennae black or brown, short acuminate (Fig. 16). 

 Mesonotum subopake, cinereous, brownish medianly, rather distinctly 

 white pilose ; scutellum more shining ; pleurae and metanotum cinere- 

 ous ; humeri and halteres yellow. Abdomen polished, but first gener- 

 ally, narrow apical margins, lateral angles and ventral margins of fol- 

 lowing segments, cinereous ; lateral apical margins of latter of yellow 

 ground color; all segments increasing in length. Ovipositor yellow, 

 stout, gradually tapering from, and slightly longer than its elongate- 

 subglobose, shining black base ; extending to apex of second segment ; 

 straight or slightly curved down (Fig. 87). Legs yellow with coxae 

 and broad femoral rings black ; femora moderately stout, with one 

 surface polished, strongly spinose; middle pair with posterior series of 

 yellow hairs ; apical and basal post-tarsal joints in proportion 1 : 2.5 ; 

 claws much longer than joint. Wings more or less brownish (Fig. 

 146). Length, 4.5 to 5.6 mm. ; wings, 5.3 to 6.4 mm. 



Type.— Brattleboro, Vt., July 15, '08 (Figs. 16, 87, 146, 

 Johnson, B. S. N. ./.). 



Paratypes. — Penobscot Co., Me. (1, Cushman, B. S. N. H.); 

 Kingston, R. I. (1, Barlow, B. S. N. H.); New York, 1; 



TRANS. AM. ENT. SOC, XXXVI. (39) JANUARY, 1911. 



