AMERICAN DIPTERA. 311 



in rather damp grass lands where they are found clinging to 

 the grass stems. I have found many specimens, but they 

 show little variation except in the intensity of the black 

 markings of the legs. 



HOLOPOGON. 



Holopogon Loew, Linnaea Ent., II, 473, 1847. 

 Holopogon Schiner, Fauna Austr., I, 129, 1862. 



Small species. Head proportionately rather broad (PI. V, 

 fig. 5), but not at all "goggle-like" as in Holcocephala; face 

 of average equal breadth, only very greatly swollen, without 

 protuberance; mystax extends up to the antennas, composed 

 of very fine outstanding pile. Front above somewhat broader; 

 vertex but slightly hollowed out, ocellar tubercle distinct; the 

 front and occiput usually well clothed with fine erect pile. 

 Antennae (PI. IV, fig. 7) nearly approximate, short, slender; 

 first two segments cylindrical, subequal, the first a trifle 

 longer, the third segment longer than the first two taken to- 

 gether, tapering toward the tip; style very slender, likewise 

 tapering, nearly or quite as long as the third segment; both 

 the first and second segments with long bristly hairs beneath. 

 Thorax short, dorsum strongly arched, usually with pruinose 

 markings, and sparse, erect, fine pile; pleurae more or less 

 pilose. Abdomen rather cylindrical, somewhat flattened, 

 usually polished, with very fine microscopic pile on the tergum, 

 with longer pile on the sides at base, and on the venter; male 

 genitalia small. Legs rather slight, the front tibiae without a 

 terminal claw-like spur; the hind tibiae very much thickened, 

 their metatarsi likewise greatly thickened and swollen; pul- 

 villi normal. The femora clothed with delicate pile, the tibiae 

 and tarsi with fine pile and longer bristly hair. All the sub- 

 marginal and posterior cells of wing wide open; the fourth 

 only slightly narrowed; anal cell closed and with a short 

 peduncle ; the second posterior cell long and narrow. 



The species of this genus, now known, are small, ranging 

 from four to eight millimeters ; usually of a general black color, 

 and with fine outstanding pile on head, thorax, and on the 

 abdomen on sides at base and venter. The species as a whole 



TRANS. AM. ENT. SOC, XXXV. AUGUST, 1909 



