AMERICAN DIPTERA. 257 



lowish. Abdomen very slender; with very sparse microscopic pile, 

 which is longer but scarcely noticeable on the sides of segments 1 and 

 2. Coxas reddish-yellow, white pruinose, the fore and middle pairs 

 with whitish pile; femora black, the lower half wholly reddish-yellow; 

 front and middle tibias reddish except narrowly on the inside where 

 they are black; hind tibis slender, incrassate at tip, black, extreme 

 base reddish; tarsi black; metatarsi unusually large. Pile of legs 

 sparse, whitish; that on the under side of the hind femora and tibias 

 quite dense, very short, pure white; bristles of tibiae sparse. Claws 

 black, narrowly reddish at base; pulvilli pale. Wings darkish hyaline; 

 all the posterior and the anal cells open. 



Type. — American Museum, A single male specimen. 

 Habitat.— M.ontereY Co., Cal. (July 2, 1896, W. M. Wheeler). 



CYRTOPOGON. 



Cyrtopogon Loew, Linnaea Ent., II, 516, 1847. 

 Euarmostus Walker, Dipt. Saund., 102, 1851. 

 Cyrtopogon Schiner, Fauna Austr., I, 133, 1862. 

 Cyrtopogon Osten Sacken, West. Dipt., 294, 1877; Cat., 1878, 

 note 104. 



Small to medium-sized species, usually quite pilose and with 

 pruinose bands upon the abdomen. Head broader than high, 

 in typical species the face in profile swollen or gibbose, and 

 clothed with an abundance of pile; front tibiae without a ter- 

 minal claw-like spur; fourth posterior cell of wing open, the 

 anal cell narrowly so. Antennse three-jointed, the third seg- 

 ment with a distinct, rather stout style, less than one-half as 

 long and under the compound microscope, plainly two-jointed, 

 the basal segment being short and about one-sixth as long as / / 

 the second. In Lasoipogon, it is the terminal segment of the " - 

 style that is long and the basal one short. Thorax moder- 

 "ately well arched, usually very pilose, and with the ground 

 color partially obscured by a pattern in grayish bloom; ab- 

 domen normally long and slender; legs normal, the pulvilli 

 and empodia well developed; the marginal, posterior, and anal 

 cell of the wing open. 



The structural characteristics of the numerous species be- 

 longing to this genus will facilitate a subdivision of the genus 

 when sufficient amounts of material is at hand to make it 

 worth while. I have followed Osten Sacken's paper on Cryto- 



TRANS. AM. ENT. SOC, XXXV. (33) JULY, 1909. 



