FUNGUS GNATS OF NORTH AMERICA. 293 



Table of species. 



a. Thorax yellow; not vittate; abdomen of the male with narrow 

 dorsal, ventral and lateral longitudinal stripes ; abdomen of the 

 female, brown. I. flava. 



aa. Thorax dark, or else with dark stripes. 



b. Thorax dark, not vittate, abdomen unicolored. 



c. Third vein strongly bowed forward toward its apex ; costal 

 vein extends slightly over 1-2 way from apex of Rs to that 

 of Mi; the media forking nearly 1-2 way between the cross- 

 vein and the fork of the cubitus; male. 2. pygophora. 

 cc. Costal vein but slightly produced. See Boletina nacta. 

 bb. Thorax yellowish or with distinct vittse. 



c. Abdominal segments with yellow posterior margins in the 

 female, or with lateral spots in the male. 3. flavicauda. 



cc. Abdomen unicolored. 



d. Costa produced scarcely half way from the tip of Rs to 



that of Mi; wing hyaline. 4. gracilis n. sp. 



dd. Costa produced fully half way from the tip of Rs to that of 



Mi; wing more or less cinereous. 



e. Subcosta ends in the costa about opposite middle of R-M 



crossvein ; veins margined with cinereous ; female. 



5. lepida n. sp, 

 ee. Subcosta ends noticeably distad of middle of the R-M 

 crossvein ; apex of wing more or less cinereous. 



6. modesta n. sp. 



I. Coelosia flava Stseger. 

 Kroyer's Tidsskr. Ent. 237. 1840. (Boletina). 

 Male and female. Length 4-4^ mm. Yellow, antennae and 

 tarsi darker, abdomen of the male with a slender dorsal, ventral 

 and 2 lateral blackish lines ; sixth segment wholly blackish ; 

 abdomen of the female sordidly brown. An European species 

 said to occur also in the United States. 



2.. Coelosia pygophora Coquillett. 

 Proc. Entomol. Soc. Wash. VI. 170. 1904. 

 Male. Length 3 mm. Black, the first 2 joints of the anten- 

 nae, a large humeral spot, the hypopygium, halteres, coxae, 

 femora, tibiae and bases of tarsi, yellow. Body thinly grayish 

 pruinose, the hairs yellowish, the bristles on sides of thorax 

 and the hairs of the hypopygium chiefly brown ; hypopygium 

 very large. Wings grayish hyaline, subcosta terminating in the 

 costa slightly before the base of the radial sector; the radial 

 sector strongly bowed forward toward its apex ; costal vein ex- 



