140 Proceedings of the Biological Society of Washington. 



medianly. Head-vestiture of black and pale yellowish hairs, the black 

 ones predominating on middle of frons, the pale ones on lower half of 

 face, occiput and orbits. Antennae black ; first joint moderately long and 

 slender; second joint less than half the length of the first, much enlarged 

 distally ; third joint stout, distinctly shorter than the first, thickened to 

 basal third and beyond tapered to a sharp point; arista coarse, black, 

 about as long as the third joint. Mesonotum shining black, clothed 

 throughout with short, coarse, black pile, densest towards margins. 

 Scutellum short and broad, the posterior margin irregularly rounded, 

 unarmed ; vestiture of dull ochreous yellow pile. Abdomen elongate- 

 ovate, flattened, much broader than the thorax, black, basally shining, 

 beyond base of second segment rugose and clothed with very short black 

 pile ; a small patch of pale hairs at posterior angles of second segment. 

 Venter wholly black. Legs black and black-haired, the tibiae with pale 

 yellowish hairs along the outer side; tarsi of all the legs ventrally with 

 cushions of ferruginous pile. Pulvilli pale ferruginous; claws black. 

 Wings broad, grayish hyaline ; posterior angles of first posterior and discal 

 cells roundedly produced, the former with a stump projecting at the loca- 

 tion of the angle. Halteres pale yellow. Length: Body about 14 mm., 

 wing 10.5 mm. 



Claremont, California, one female (F. R. Cole). 



Type: Cat. no. 21,416, U. S. Nat. Mus. 



The specimen was generously presented to the national collection by 

 Mr. Cole. The close relationship of this species with modestus and colora- 

 densis is obvious through both structural and coloration characters ; how- 

 ever, differences exist which leave no doubt that these forms are specifically 

 distinct. 



Microdot! rufipes (Macquart). 



Aphritis rufipes Macquart, 1842, Dipt. Exot., vol. 2, pt. 2, p. 11, pi. 2, 



fig. 3. 

 Microdon limbus Williston, 1886, Synopsis No. Amer. Syrphidse, p. 8. 



Williston's type, which is before me, agrees in every way with Mac- 

 quart's description. In addition there are before me, a male from Jack- 

 sonville, Florida (W. H. Ashmead), and a female from Newport News, 

 Virginia, taken September 3, 1910, by E. W. Wall. Macquart's specimen 

 is stated to have come from Philadelphia. 



Microdon fulgens Wiedemann. 



This is a large, robust, brilliantly metallic colored species originally de- 

 scribed from Georgia. The species figures in some collections under the 

 name aurifex, but it would seem incorrectly. It may be that the Mexican 

 specimens so reported really belong to aurifex ; at all events, M. trochilus 

 Walker, from Mexico, so referred, is stated to have the abdomen clothed 

 with pale yellow hairs, as in a specimen from Para, Brazil, reported un- 

 der aurifex by Macquart. The original description of aurifex, unfortun- 



