NO. 2024. FLIES IN SUBFAMILY BOTANOBIIN^—MALLOCn. 255 



Without examination of more specimens I consider it unwise to give 

 this form specific rank. 



There are several specimens in same collection from Trinidad 

 River, Panama, March 29, 1912 (A. Busck), which resemble the 

 above specimen very closely, differing principally in size, being about 

 3 mm. as against 2 mm. Amongst these specimens there are some 

 that represent different forms which are ranked as species at present 

 and which cause me to have doubts as to the validity of these 

 specific values. It is impossible, however, to say definitely whether 

 the forms here listed are good species or only varieties without 

 rearing them. 



17. mPPELATES DORSATUS Williston. 

 Hippelates (Siphomyia) dorsatus Williston, Trans. Ent. Soc. Lond., 1896, p. 419. 

 This is merely a variety of plebejus, in which the yellow color of 

 thorax is more than usually pronounced. 

 Described from St. Vincent, West Indies. 



GROUP E. 



Species with Mesonotum Yellow, or Eeddish, Without Stripes. 



18. HIPPELATES TENER Coquillett, 

 Fig. 30. 

 Eippelates tener Coquillett, Proc. U. S. Nat. Mus., vol. 22, 1900, p. 265. 



Female. — Reddish yellow, shining; frons pale yellow anteriorly, 

 becoming brown toward vertex; triangle narrowly gray dusted on 

 margins, more broadly at posterior lateral angles, and on ocellar 

 region, glossy red brown in center; occiput grayish; third antennal 

 joint browned above; proboscis brown. Disk of mesonotum some- 

 times brownish, always with distinct pollinosity; upper half of 

 pleurae gray poUinose, lower half glossy. Abdomen reddish brown, 

 basal segments and apices of segments yellowish. Legs yellow, 

 blackened on fore tarsi, slightly on mid and hind femora at middle, 

 and distinctly on apices of hind tibiae as well as mid and hind tarsi. 

 Wings grayish, veins brown. Halteres yellow. Bristles and hairs 

 black, or brownish. 



Frons short and broad, occupying almost one-half the width of 

 head ; outline of triangle rather indistinct, but traceable almost to eye 

 margin at vertex, rounded in front, and extending to over middle of 

 frons; surface hairs distinct, antennae rather above average size, 

 third joint rounded, arista not as long as width of frons, pubescent; 

 cheek not very high, about half as high as third joint of antenna, 

 not produced anteriorly; proboscis short, thick, the apical portion 

 turned back for a short distance; eyes bare, slightly higher than 

 long. Mesonotum impunctate, but with two very faint sulci, 



