AMERICAN DIPTERA. 179 



hair; third segment one and one-half times longer than the 

 basal segments taken together, elongate, with a constriction 

 a little before the middle, with a slight incrassation just 

 beyond; style short, less than one-fifth the length of the 

 third segment, cylindrical and bearing a terminal microscopic 

 bristle. Eyes with the facets of the middle region very much 

 enlarged. Thorax well arched, scutellum large; besides the 

 usual clothing of hair and bristles, with conspicuous hair and 

 bristles on the anterior part on either side of the median 

 stripe; the median stripe divided by a row of fine bristles; 

 the hair of the anterior part of dorsum and above base of 

 wings sometimes nearly scale-like. Scutellum with a row of 

 long erect bristles on the posterior margin. Pleuras nearly 

 devoid of pile; trichostical hair long. Abdomen rather nar- 

 row, moderately convex, flatter in the female than in the male, 

 gently tapering toward the tip; male hypopygium rather 

 small; ovipositer with the usual circlet of spines; sides of the 

 first segment with a few bristles and longer pile; remainder 

 of abdomen, especially on the sides and the venter, with 

 rather sparse short pile. Legs of moderate length and stout- 

 ness, covered with much hair, which is characteristically 

 depressed and beset with numerous erect bristles, not only 

 on the tibiae and tarsi, but also on the upper and posterior 

 sides of the fore and the upper and anterior sides of the middle 

 and hind femora. Claws remarkably long; pul villi entirely 

 wanting. Wings as in Cyrtopogon; all the five posterior cells 

 wide open ; the anal cell narrowly so ; the small cross-vein 

 little beyond the middle of the discal cell. 

 Type. — Ablautus trifarius Loew. 



SYNOPSIS OF SPECIES. 



1 . Abdomen wholly black 2. 



Abdomen reddish or yellow 4. 



2. Femora brownish; length 6-7 mm trifarius. 



Femora black 3 . 



3. Tibiae black miimis. 



Tibise reddish-yellow rufotibialis. 



4. Pleuras for most part polished rubeiis. 



Pleurae wholly pruinose flavipes. 



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



