Fossorial ITt/menojytera of North America. 421 



unusually long and small, hirsute. Abdomen equalling in length the 

 head and thorax, long and narrow, oval lanceolate, tip with three 

 seta;. 



9 . Antennae long filiform, joints a little thickened at the sutures, 

 abdomen with a broad sub-triangular supra'anal area at tip. The species 

 are highly colored, red and yellow on the thorax and abdomen. 



This genus will be easily known by its very elongated propodeum 

 and thorax generally, reinindiug us of Passalxcw, and also strongly 

 mimicking the Pompilidte, as the elongated form is a sign of degrada- 

 tion. The unusually long and narrow propodeum suddenly truncated, 

 with the edges rounded off, the broad wings with unusually broad and 

 short cells, the minute appendiculated 2d sub-costal, and the gay co- 

 loration of the species, together with the great disparity of the sexes, 

 renders the genus a very interesting one. 



Shuckard remarks that the front edge of the clypeus is bi- or tri- 

 dentate. That of our species is smooth, not indented, and the labrum 

 is very distinct, crescentic in shape, but narrow and short compared 

 with some other genera of the family. 



Alyson oppositus. Say. 



A. opjjositus, Say, Bost. Jour. Nat. Hist., i, p. 380. (1837). 

 Smith, Cat. Ilym. Br. Mus., iv, p. 373. (185G). 



% . Body deep shining jet black; head smooth, shining, imper- 

 ceptibly punctured, with a fine pubescence; orbits yellow towards the 

 clypeus, which is black, thinly pubescent; mandibles yellow; palpi 

 yellow testaceous, joints long and slender, brown at base; antennas 

 brownish black throughout. Thorax black throughout, very slightly 

 punctured and pubescent. Propodeum with five rows of fossae, of 

 which the mesial is the largest, and is dilated at the apex of the en- 

 closure, from which on the flanks diverge coarse parallel, quite regular 

 striae, becoming smaller on the flanks, and towards the insertion of the 

 abdomen very irregular and numerous. Wings clear transparent, im- 

 maculate ; nervures dark brown ; fore trochanters pale at tip, femora 

 black, sericeous, fore and middle pairs tipped slightly with yellow; fore 

 and middle tibiae yellow, brownish above; hind tibias brown, hirsute, 

 spurs testaceous; tarsi pale brown, sericeous. Abdomen wholly black, 

 polished and shining, with two remote round yellow spots on the second 

 ring, tip slightly hirsute, with three setaj. 



Length, .22 — .30 inch. 



2 . Front broader than in $ , clypeus yellow, flagclluin fuscous be- 

 neath at base. The basal joint of the abdomen is red in my speed- 



