46 PKOCEEDINGS OF THE NATIONAL, MUSEUM. vol.63. 



15. PLATYGASTER NIGRIFEMUR (Ashmead). 



Ectadius nigrifemur Ashmead, Bull. No. 1, Col. Biol. Assoc, 1890, p. 10. 

 Polymecus nigrifemur (Ashmead), Ashmead, Bull. 45, U. S. Nat. Mus., 1893, 

 p. 280. 



Female. — Length 3 mm. Head more or less oblong seen from above, 

 with the angles rounded, somewhat less than twice as wide as long, 

 slightly emarginate behind, subconvex in front, a little wider than the 

 thorax; head entirely uniformly shagreened and shining except just 

 above the bases of the antennae where it is transversely aciculate; 

 cheeks convex, subangulate exteriorly, and wider antero-posteriorly 

 than the eyes; pedicel twice as long as wide, as long as joints three 

 and four united, as wide as four, slightly wider than three; joint 

 three as long as wide, scarcely narrowed basally; four a little longer 

 than wide, subequal to five and six, cylindrical, not narrowed api- 

 cally or basally; joints seven to nine about as wide as long; ten a little 

 longer than three and four united, subacute apically, the sides curved; 

 thorax two-thirds as wide as long, as wide as the abdomen, flattened 

 above, higher than wide; pronotum finely shagreened laterally; meso- 

 notum shagreened, except medially on the lateral lobes; notauli com- 

 plete, the median lobe pointed apically; scutellum transverse, convex, 

 shagreened, margmed laterally, pubescent on the sides; metapleurae, 

 propodeum, first tergite laterally, first sternite, and second in the 

 f o veae, densely covered with matted silvery hairs ; abdomen one and 

 seven-tenths times as long as the head and thorax united; median 

 area on first tergite not sharply defined, longer than wide, with sev- 

 eral short carinae basally; basal foveae on second tergite broad and 

 deep, polished as is also the rest of the abdomen; median area un- 

 soulptured; wings hyaline, extending slightly beyond the apex of the 

 fifth tergite. Black; antennae piceous; legs brown. 



Male. — Length 2.5 mm. Joint three of antenna half as long, and 

 about half as wide as four, as wide as long; four a little wider than 

 long, cylindrical, curved above, wider than any of the following joints, 

 as long as the pedicel; joints five to nine a little longer than wide; 

 ten longer than three and four united, sharply pointed apically, the 

 upper side regularly curved; abdomen elliptical, longer by the length 

 of the first segment than the head and thorax united, a little over 

 twice as long as wide, narrowly truncated apically; segments three 

 to seven united about half as long as the second ; wings reaching the 

 length of the last two segments past the apex of the abdomen. 



Type locality. — Greeley, Colorado. 



Type.— Csit. No. 2123, U.S.N.M. Type female and allotype male 

 selected. 



Redescribed from the type series, two females and three males, in 

 the ooUection of the National Museum at Washington. One female 

 type has the head and wings lost. All specimens mounted on card 

 points. 



