418 Professor Williston on the 



15. Thorax shining black 5 



Thorax not wholly black 4 



4. Thorax reddish-yellow ; front black ; second and third 



sections of the costal vein of nearly equal length 



equalis, n. sp. 

 Mesonotum brown or blackish ; front yellow, with a 

 moderate-sized brown triangle ; second section of 

 the costal veia much longer than the third 



(lormlia, Loew. 



5. Scutellum black ; third section of the costal vein much 



shorter than the second flavipes, Loew. 



Scutellum reddish ; second and third sections of the costa 



of nearly equal length scutellaris, n. sp. 



1. Hippelatcs (n, subg., Si'phomyln) lyrohoscideus, n. sp. 



^ . Front opaque yellow, the vertical triangle black, but 

 covered with light greyish dust, leaving a small, rounded, shining 

 spot near the ocelli. The triangle reaches to about the middle of 

 the front, and its sides are nearly equilateral ; a row of small 

 bristles on either side reaches to below the middle of the front. 

 Antennas, face, cheeks and palpi wholly yellow ; on either side of 

 the oral margin in front a small vibrissal bristle. Proboscis slender, 

 elongate, bent near its middle and turned back, its slender proximal 

 portion a little shorter than the length o£ the head. Cheeks rather 

 broad. Palpi cylindrical, a little broader toward the end. Thorax 

 black, thickly greyish dusted, the mesonotum with three, slender, 

 indistinct lines; the pleuraa sliining black on the lower portion. 

 Scutellum oval, with two bristles on its border. Abdomen red or 

 brownish-red ; in some specimens reddish-brown with yellowish 

 incisures. Legs wholly light-yellow ; spur of the hind tibiae long 

 and stout. Wings cinereous hyaline ; third section of the costa 

 short. Length 2 mm. 



Ten specimens. St. Vincent. This and the following 

 species, while agreeing sufficiently well in the other 

 characters with the genus Hippelafes, I have thought 

 well to distinguish subgenerically from the other species 

 by the name Sij^homyia, on account of the elongate 

 proboscis. Others of the previously described species 

 evidently belong to the same subdivision. 



