osten sacken on western diptera. 289 



Ablautatus. 



A new genus, established by Dr. Loew (Oentur,, vii. 63) for a Galifor- 

 nian species, under the name of Abkmtus; modified later (Berl. Bnt. 

 Zeit., 1874, 377) in Ablautatus. The species, A. trifarius, is described 

 from a female specimen. 



I have a male and two females which undoubtedly belong to this 

 genus, but apparently to a different species, as the legs are altogether 

 black, and beset with white spines, including the tarsi. I caught my 

 species in company with Clavator sahulomim, which seems to mimic 

 it, as its body is almost exactly of the same coloring; both occur on 

 sandy soil. 



Tbe genus is easily recognizable by its large ungues and the total 

 absence of pulvilli. 



The following generic characters belong to A. mimus, but seem in the 

 main to agree with A. tr if arms. 



Front and /ace comparatively narrow ; face almost flat, with a dense 

 mystax, reaching nearly up to the antennae ; front very little broader 

 above. 



Antennas. — Third joint by about one-half longer than the two first taken 

 together, elongated, with a coarctation a little before the middle, and a 

 slight incrassation beyond the middle (not unlike the third joint in an 

 ordinary Cyrtopogo7i, only both the contraction and expansion are more 

 marked) ; antennal style short, less than one-fifth the length of the joint, 

 cylindrical, with a microscopic bristle ; the two basal joints of the an- 

 tennge have, on the under side, several conspicuous bristles, some of them 

 more than half the length of the antennse ; some very small hairs on 

 the upper side. 



Thorax. — Besides the usual hairs and bristles, there are some conspic- 

 uous bristles on its front part, on the sides of the median stripe, which 

 do not exist in Cyrtopogon ; scutellum with a row of long, erect bristles 

 on its edge. 



Eyes with the facets of the middle region very much enlarged (much 

 more so than in Clavator). 



Abdomen rather narrow, moderately convex, flatter in the female than 

 in the male, gently tapering toward the tip ; male hypopygium rather 

 small; ovipositor with the usual star of bristles. At the base, on the 

 sides, the usual long hair, besides which, on the first segment, a fan- 

 like row of bristles is perceptible, which are white in A. mimus, and are 

 described as " lutescent " for A. trifarius. I believe I see similar, but 

 shorter, spines on the following segments, but thej^ are white, like the 

 pubescence surrounding them, and difficult to distinguish from it. Be- 

 sides the longer white pile on the under side, the sides of the abdomen 

 and the hypopygium are clothed with short, more or less recumbent, 

 white pile. 



Legs of moderate length and stoutness, very hairy, and beset with 



