220 DIPTERA OF NORTH AMERICA. [PART II. 



striking. The upper part of the pleurae is covered with gray dust 

 and the bristles above the fore coxae are of a pale color. The 

 abdomen is less thickly dusted than the thorax, appears however 

 rather gray in some directions on account of its cover of dust. 

 The peduncle of the hypopygium is so short as to appear ses- 

 sile ; it is rather stout, ovate, almost reversed-pyriform, black, 

 polished on its entire right side and on the latter half of the left 

 side. Coxae black. Feet brownish-yellow, all femora, from the 

 root as far as the middle, pitch-black, this color vanishing gradu- 

 ally. Cilia of the tegulae whitish ; halteres whitish with a darker 

 peduncle. Wings hyaline, scarcely tinged with a little gray, 

 veins brownish ; the posterior transverse vein distant from the 

 margin of the wing more than its own length. The third longi- 

 tudinal vein ends a little farther from the tip of the wing than 

 in the preceding species ; the last segment of the fourth longi- 

 tudinal vein is also very straight, converges, however, less towards 

 the third longitudinal vein than in M. nigripes. 



Hab. Florida. (Osten-Sacken.) 



Observation. I have received from Mr. Le Baron two females, 

 captured in Illinois. They are somewhat larger than the above 

 described male, and the lower part of the face is greenish-blue, but 

 very little shining. Otherwise they agree with it perfectly. The 

 different color of the lower part of the face would be a sufficient 

 specific distinction, if the bad condition of the above described 

 male of M. veles did not admit the supposition that the difference 

 in its color is an unnatural one. I prefer therefore not to consider 

 these females as belonging to a different species. 



Gen. XL. CHRYSOTIMUS. 



Characters. Size of the body small. Antennae small ; their 

 first joint glabrous ; the third joint very short, usually broader 

 than long, distinctly hairy, with an apical or almost apical arista. 

 Eyes with a very short pubescence. The posterior end of the 

 thorax with a rather large, distinctly concave, sloping area. 

 The bristles upon thorax and scutellum yellow. Abdomen in all 

 the species partially yellow. Feet not elongated ; the first joint 

 of the hind tarsi without bristles. Posterior transverse vein upon, 

 or more or less before, the middle of the wing ; the last segment 

 of the fourth longitudinal vein neither broken nor distinctly bent 



