NO. 2024. FLIES IN SUBFAMILY BOTANOBIIN^—MALLOCH. 253 



equal to diameter of tibia. Wing with third costal division two- 

 thirds as long as second; veins 3-4 parallel. 



Length, 2-2.5 mm. 



Redescribed from type. Locality, San Mateo County, California 

 (Baker). 



There is a single specimen in the U. S. National Museum collection 

 from Motzorongo, Vera Cruz, Mexico, February, 1892 (H. Osborn), 

 which dififers slightly from the type, but not to such an extent that I 

 consider it necessary to describe it as another species. 



Becker records microcentrus from Bolivia. 



GROUP D. 



Species with Mesonotiim Black, Thickly Gray, Dusted on Disk; Legs 

 Almost Entirely Yellow. 



14. HIPPELATES PLEBEJUS Loew. 

 Figs. 15, 17. 

 Hippelates plebejus Loew, Dipt. Amer. Sept. Ind. Cent., 3, 1863, species 68. 

 Female.— Blsick, slightly shining; frons yellow, triangle black, 

 thickly gray dusted; antennae yellow, third joint rarely darkened on 

 upper surface; face and cheeks yellow; back of head black; pro- 

 boscis black, glossy; palpi yellow. Mesonotum thickly covered with 

 yellowish or grayish pollmosity; humeri, upper parts of pleuras, and 

 hind margin of scutellum generally yellow. Abdomen black with 

 yellow hind margins to segments, yellow with black fore margins to 

 segments, or yellow with three longitudinal rows of black spots. 

 Legs entu-ely pale yellow. Wings clear; veias yellow. Hal teres 

 yellow. Bristles and hairs on body yellow; apical spur on hind tibia 

 black. 



Frons about one-third broader than either eye; triangle occupying 

 almost entire width at vertex, forming an equilateral triangle, 

 and extending to middle, or slightly beyond middle of frons; surface 

 hairs on frons numerous, but not very distinct; anterior margin of 

 frons slightly protruding; antennse of moderate size, third joint 

 rounded; arista not as long as width of frons, slightly pubescent; 

 cheek about equal in height to breadth of third antennal joint, the 

 anterior margin slightly produced; eyes bare, sUghtly higher than 

 long. Mesonotum with three rather indistinct lines of shallow 

 punctures, the disk with numerous, closely placed, short hairs; 

 scutellum rounded in outline, the posterior margin with two long and 

 two short bristles, the long ones not approximated at the base, 

 disk with numerous short hairs. Surface hairs on abdomen short. 

 Legs moderately stout; hind femora slightly thickened; hind tibial 

 spur very long, and much bent, reaching to beyond middle of meta- 

 tarsus, situated close to apex; hind metatarsus attenuated at base. 



