NORTH AMERICAN DIFTKRA. 127 



SIIMIOPIIVTOn. gen. 

 Small, blackish species, tlie abdominal segments edged basallv with 

 silvery. Belongs in Phytoinse. Head nearly rectangular in profile ; 

 front hardly prominent, from two-fifths to three-sevenths width of 

 face (? $ ), slightly wider before than at vertex, face a little wider 

 still ; frontal bristles in a single row descending to base of third an- 

 tennal joint, vertical and next two bristles stoutest, directed back- 

 ward ; two orbital bristles directed forward (9)- Face nearly per- 

 pendicular; ejjistoma rather prominent, oral margin with a Q-shaped 

 cleft in niitldle ; facial depression occupying about seven-ninths width 

 of face, moderately deep, wider below ; facial ridges bare, except two 

 or three bristles next vibrissie, constricted below ; sides of face very 

 narrow, bare; cheeks less than one-fourth eye-hight, bare except a 

 few hairs posteriorly and some bristles on lower border; vibrissa 

 rather strong, but not decussate, inserted at a considerable distance 

 from oral margin, but on a line with upper portion of cleft. Eyes 

 bare, descending almost as low as vibrisste. Antennae hardly or a 

 little shorter than face, inserted high, first two joints short, third 

 joint four or more times as long as second, nearly straight or some- 

 what dished on front edge, posterior apical corner rounded ; arista 

 not longer than third antennal joint, microscopically pubescent, 

 thickened two-thirds or more of its length, ta])ering to point, 8-jointed 

 and hardly or distinctly geniculate, first joint indistinct, second con- 

 siderably elongate and distinctly bowed. Proboscis one to one and 

 one-half times as long as bight of head, slender, straight below gen- 

 iculation, with very small labella; palpi slender, not long, more or 

 less thickened at tip. Thorax as wide as head ; scutellum with an 

 apical, slightly or not decussate, pair of macrochictit reaching to 

 base of third abdominal .segment, a shorter lateral pair, and a weak 

 subdiscal pair. Abdomen not wider than thorax, rather oval, not 

 elongate, first segment not shortened, though appearing strongly so 

 from above; macrochsetie only marginal, unless on anal segment. 

 Legs not stout, only fine bristly ; metatarsi nearly as long as follow- 

 ing joints together; claws and pulvilli very short. Wings a little 

 longer than abdomen, with sn)all costal spine, third vein spined at 

 base, or nearly to small cross-vein ; apical cell closed in margin at 

 tip of wing; fourth vein curved at an oblique angle, without stump 

 or wrinkle, apical cross-vein nearly straight ; hind cross-vein nearly 

 straight, almost perpendicular, in middle between small cross-vein 

 and bend of fourth, or slightly nearer to small cross-vein. Type, 

 S. Jlorideiisis n. sp. 



TRANS. AM. ENT. SOC. XIX. M.\Y. ISttJ. 



