16 « S. W. WILLISTON, M. D. 



and is a little more elongate. My determination of the species may, 

 however, be incorrect; the dorsum of the abdomen is not glabrous, the 

 pile on the under side is white, not yellow, the tibiae are wholly yellow, 

 and the length is not more than 10 mm. 



26. Anisopogoii laiitu!« Loew, Centur. x, 34. 



Two female specimens from Washington Terr, and California. Wholly 

 black, with thick white pile below. Abdomen nearly bare above, tibiae 

 and tarsi red, the middle legs without the tufts of black pile, and the 

 wings pure hyaline (in one specimen slightly clouded along the veins 

 near the base). The specimens agree very well with Loew's description, 

 still a comparison of the males is needed. 



BflCOCLrES. 



? Leptarthras Stephens, Cat. Brit. Ins., JS29. 



f Isopogon Loew, Linnea Entom. ii, 384, 1847. 



? Apkamartania Schiner, Verb. Zool. Bot. Ges., 1866, 671. 



Pygostolun Loew, Centur, vii, 28, 1866, (Preoc.) 



Nicocles Jaennicke, Neue Exot. Dipt. 47, 1867. 



According to the researches of Prof. Brauer, (Ueber die Gattung 

 Isopogon, Loew, Wien. Ent. Zeit. ii, 5.':5) it appears that the type of 

 Isopogon Loew (/. brevirosfris Meig. ) has terminal spurs on the front 

 tibiae, a fact which had not only been overlooked by previous authors, 

 but the absence was considered by both Loew and Schiner as a generic 

 character ! With the presence of this spur the genus presents strong re- 

 lationship with Nicocles, and is by Brauer considered synonymous. This, 

 however, to me seems somewhat doubtful. /. brevirostris as Schiner 

 describes it, differs too much in the structure of the hind legs, viz : " Die 

 Hinterschienen sind an der Wurzel schmal, werden aber plotzlich breit 

 undplump, und verschmalern sicli wieder gegeu die spitze zu; die hinteren 

 Metatarsen des Mannchens sind messerartig zusammengedrtickt, viel 

 langer als die Schieneii, fast fiinfmal so lang als die iibrigen Glieder 

 zusammen, bei dem Weibchen von gewohnlicher Bildung, etwas ver- 

 dickt" (Faana Austr. i, 131). This peculiar structure of the male tarsi 

 was the character upon which Leptarthrus of Stephens was based, the 

 typical species of which was the same. In five species of Nicocles known 

 to me, the structural characters are all uniform, the hind tibiae are thick- 

 ened at the extremity (similar to Holopogon), the hind tarsi- are much 

 thickened, but are alike in both sexes, the metatarsi scarcely more than 

 a fourth of the length of the hind tibiae. Moreover, in the structure of 

 the male abdomen and in the peculiar silvery markings so constant in all 

 the species, Nicocles seems to show a sufficiently important difference. 



