AMERICAN DIPTERA. 159 



Leptoga.ster aiiuulatus. 



Leptogaster annulatus Say, Jour. Acad. Sci. Phil., Ill, 75, 1823; 



Comp. Works, II, 68. 

 Leptogaster histrio Wiedemann, Auss. Zw., I, 535, 1828. 

 Leptogaster histrio Wiedemann, Schiner, Verh. Zool.-Bot. Ges., 

 XVII, 356, 1867. 

 rj* 9. — Length 8-11 mm. — Face and mystax white, thorax pinkish, 

 thinly whitish pruinose; abdomen blackish with white bands. Em- 

 podia wanting. 



Head black; face and occiput white pruinose, mystax white, pro- 

 boscis black, at base yellow. Antennae pale straw colored, third 

 segment elongate oval, shorter than the style, sometimes dark. Thorax 

 pinkish, with three dilated pale brown stripes on the dorsum. Abdo- 

 men dark, from almost quite black on the distal segments to pale on 

 the proximal ones; distally, in the female, strikingly dilated: segments 

 2-6 with a distinct yellowish white fascia about the posterior margin. 

 Legs pale straw; the tarsi, excepting their tips, almost white; front 

 and middle femora tipped with black; the hind pair incrassate, the 

 slender portion sordid white, the incrassate portion dark brown with 

 a wide yellowish-red band. Hind tibiae five-banded as follows: — bands 

 one, three, and five, dark brown, the proximal one bordering on red; 

 band two, white; band four, yellowish. Claws black, empodia wanting. 

 Wings pure hyaline, violaceus; the second posterior cell not elongated, 

 and the fourth sessile or subsessile. 



Type. — -Lost. 



Habitat.— Mass.; N. Y.; Pa. (type); N. J. (July 25, Aug. 

 23; E. Daecke); D. C. (Aug. 23); N. C. ; Southern Ga. (Mor- 

 rison); Ark.; Yucatan (G. F. Gaumer). 



This species is recognized at once by its pinkish thorax and 

 the distinct and striking color markings of the legs and the 

 absence of empodia. These latter are present in all other spe- 

 cies of Leptogaster except schcefferi, known to me from America, 

 north of Mexico. Described from fourteen specimens. The 

 specimen from Yucatan is in the collection of the University 

 of Kansas and compares perfectly with our northern specimens. 

 There are four specimens at the M. C. Z. 



Leptog-aster atridorsalis n. sp. 



(f 9- — Length 8-9 mm. — Thorax black, anterior two-thirds of 

 dorsum bare, highly polished; posterior third, lateral margins, pleurae 

 and coxae, white pruinose. 



Head black; face, mystax and occiput, white; proboscis polished 

 dark brown. Antennae short, segments 1-2 pale straw; segment 3 



TRANS. AM. ENT. SOC. XXXV. MAY, 1909. 



