180 DIPTERA OF NORTH AMERICA. [PART III. 



possible, from Macquart's statements. The characters which 

 prevent me from uniting this genus with the following are : the 

 front, very much projecting in profile, the much shorter and 

 stronger femora, the wings, which are not attenuated towards their 

 basis, and the strong convergency of the third and fourth longitu- 

 dinal veins. If the auxiliary vein is really as far distant from 

 the first longitudinal as Macquart's figure shows it, this would 

 furnish one distinctive character more. 



Gen. IV. STEJfOMACRA nov. gen. 



Charact. — General shape almost like Sepsis. 



Front rather broad, somewhat narrower anteriorly. 



Ocelli closely approximated to each other, almost in the middle of the 

 front. 



Antennal arista with a very distinct pubescence. 



No mesothoracic and, to all appearances, no prothoracic bristle. 



Scutellum with two bristles ; metathorax sloping. 



Abdomen narrow, almost pedunculate. 



Feet slender, femora not incrassated, the intermediate ones attenuated 

 towards the end; the hind femora a little longer than *he middle 

 ones ; all are beset with spines towards the tip. 



Wings rather large, very much attenuated towards the basis ; poste- 

 rior angle rounded off; the auxiliary vein very much approximated 

 to the first longitudinal, coalescing with it at the tip; the second 

 longitudinal reaches the margin of the wing far from the apex; the 

 small crossvein is far before the middle of the discal cell; the last 

 section of the fourth longitudinal vein almost parallel to the third 

 vein ; posterior angle of the anal cell obtuse. 



1. S. Guerini Big. £ 9 .—(Tab. IX, f. 25., Rufescens, pleuris, 

 scutello, metanoto abdominisque basi nigris ; alse hyalinse, strigula 

 subbasali et macule magna apicali nigris. 



Reddish, pleurae, scutellum, metathorax and the basis of the abdomen 

 black; wings hyaline with a little black streak at the basis and a large 

 black spot at the apex. Long. corp. 0.20 ; long. al. 0.20 — 0.22. 



Syn. Sepsis Gue'rini Bigot, De la Sagra, Hist, fisica, etc., p. 822, Tab. XX, f. 9. 



Ferruginous-red, rather shining, the upper part of the occiput, 

 as well as the region of the vertex and the little stripes running 

 down from it upon the front, sometimes shining black, almost 

 metallic. Front rather broad, somewhat narrower anteriorly ; 

 the bristles of the vertex long ; the bristle in front of them, 

 inserted upon the little stripe, is likewise long, removed to almost 

 the middle of the front. The ocelli, near which the ordinary two 



