AMERICAN DIPTERA. 335 



gin; trichostical bristles long and fine. Pile of abdomen sparse, white. 

 Legs, including the coxa?, thinly whitish pruinose with white hair and 

 bristle. 



Type. — Am. Ent. Soc. of Phila. A single female. 



Habitat. — Alamagorda, N. M. (April 24, '02, H. L. Viereck). 



This is one of the smallest Asilids known to me. It seems 

 out of place beside trifasciatus, but is about the size of tener 

 and barbistrellus of Europe, specimens of which I have for 

 comparison. 



Stichopogon trifasciatus (PI. IV, fig. 9; PL X, fig. 7). 



Dasypogon trifasciatus Say, Jour. Acad. Sci. Phila., Ill, 51, 

 1822: Compl. Works, II, 64. 



Dasypogon candidus Macquart, Dipt. Exot., Suppl., I, 67, 1846. 



Thereva plagiata Harris, Cat. Ins. Mass. (mss. name). 



Thereva plagiata Walker, List, I, 223, 1848. 



Dasypogon fasciventris Macquart, Dipt. Exot., Suppl. IV, 69; 

 PI. VI, fig. 13, 1850. 



Dasypogon gelascens Walker, Trans. Ent. Soc. of London, n. s., 

 V, 277. 



Dasypogon candidus Bellardi, Saggio, II, 78, 1861. 



Stichopogon trifasciatus Williston, Trans. Am. Ent. Soc, XIII, 

 289, 1886. 



Stichopogon trifasciatus Townsend, Proc. Cal. Acad. Sci., IV, 598. 



Stichopogon trifasciatus Jones, Trans. Am. Ent. Soc, XXXIII, 

 279, 1907 (locality note). 

 d 9- — Length 9.5-14.5 mm. — Grayish-white pruinose; the tergum 

 of abdomen velvety black, trifasciate with white. Face, front and 

 occiput, silvery- white pruinose; the front often being grayish-brown 

 pruinose with a deep brown spot close to each orbit and with the orbits 

 broadly clothed with fine white pile. Mystax composed of a row of 

 sordid white bristles on the oral margin; vibrissas very slight, hardly 

 perceptible; occipital bristles whitish, short, stout, well separated, and 

 arranged in a row just behind the vertex. Posterior orbits of eyes 

 below with fine silky white pile forming a rather scant beard. An- 

 tennae black, whitish pruinose. Thorax wholly grayish-white pruinose, 

 the dorsum with microscopic black hair which is lacking on a trian- 

 gular spot on each side just behind the transverse suture and before 

 the posterior callosities. One presutural bristle just above the dorso- 

 pleural suture and one postalar on the posterior callosity on each side 

 are the only bristles on the dorsum. Scutellum with a very fine fringe 

 of microscopic pile. Pleura? nearly bare, the mesopleurse and the sides 

 of the pro thorax with slight white pile; trichostical bristles long, slender, 

 white. Halteres white. Abdomen whitish pruinose, with the excep- 

 tion of the base of the first segment, a large disc on segments 2 and 3 



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



