THE MYCETOPHILID.qj OF NORTH AMERICA. 223 



I. Genus Mycetobia Meigen. 

 Mycetobia Meigen, Syst. Beschr. I. 229. 27. 1818. 

 Head spherical, flattened in front, 3 ocelli arranged in a tri- 

 angle on the front, the anterior one smaller ; palpi 4 segmented ; 

 antennae 2-I-15 jointed, almost annular, the apical joint very 

 small. Abdomen with 7 plainly visible segments. Tibiae with 

 short and slender spurs, lateral setse of middle and hind tibiae 

 small. Wing broad (fig yy) ; subcosta about 1-3 as long as 

 the wing, subcostal crossvein wanting; R2+3 arises at the R-M 

 crossvein, R-i-f 5 ends near the tip of the wing, the costa is pro- 

 longed a little beyond it, the media arises apparently at the 

 M-Cu crossvein, though there is usually an indication of the 

 true basal section of this vein in the form of a fold-like vein 

 bisecting the basal cell ; the cubitus forks slightly praximad of 

 of M-Cu crossvein, anal vein ends in the margin of the wing. 



Mycetobia divergens Walker. 

 1856. divergens Walker. Insecta Saundersiana, Dipt. I. 418. 

 1867. persicce Riley, Prairie Farmer 15 June. vol. 35. n. s., 



V. 19, p. 397 (Mycetophila). 

 1869. sordida Packard, Guide to study of Insects. 388. 

 1903. marginalis Adams, Kansas Univ. Science Bulletin II. 



2. 21. 

 Male and female. Length 3 to 4 mm. Head black, subshin- 

 ing, tip of palpi yellow ; antennae black including the basal 

 joints. Mesonotum black, shining, humeri, lateral and pos- 

 terior margins, and scutellum with a reddish tinge, pile yellow, 

 pleura and metanotum black, mostly shining. Abdomen vari- 

 able, shining, basal segments usually more or less yellow, apical 

 segments blackish, pile yellow. Legs yellow, tarsi infuscated 

 at the tip, fore metatarsus 2-3 as long as its fore tibia. Wings 

 hyaline, subcosta ends in the costa proximad of the base of 

 R2+3; venation as figured (fig. yy). Length of wing 3 to 4 

 mm. which is 3 1-3 times as long as the fore tibia. Halteres 

 yellowish. Ithaca, N. Y. ; Boulder, Col. (T. D. A. Cockerell, 

 collector) ; Gardiner, Maine. 



• In my specimens there is considerable variation in the amount 

 of color on the abdomen, in other respects they appear identical. 

 This variation has led me to believe that the synonymy given 

 above is correct. 



