310 Maine: agricultural experiment station, iqii. 



usually forks under or proximad of the proximal end of the 

 R-M crossvein, its elongate fork narrow at the base then sud- 

 denly divergent; anal vein very stout, rather long though not 

 reaching wing margin; last anal long, incomplete, slender (Fig. 

 233). Larvse live in fungi {Armillaria, etc.). 



The elongate fork of the cubitus with its divergent branches, 

 and the strong anal vein will distinguish this genus from its 

 nearest relatives. 



Table of species. 



a. Cubitus forks nearly under the proximal end of the crossvein ; fore 

 metatarsus little if any longer than the tibia ; anal vein ends 

 distad of the fork of the cubitus; female. i. Sp. a. 



aa. Cubitus forks proximad of the proximal end of the crossvein. 



b. Fore tibia and metatarsus subequal in length ; anal vein slender, 

 produced slightly beyond the fork of the cubitus ; subcosta ends 

 in Ri ; female. 2. Sp-. b. 



bb. Fore tibia shorter than metatarsus, or otherwise distinct. 



c. Third and fourth tarsal joints of the male with a series of 



curved spines below; fore metatarsus 1.6 times the tibia in 



length ; anal vein produced beyond fork of the cubitus ; 



hypopygium small (Fig. 121). 3. serripes n. sp. 



cc. Tarsal joints without curved spines in the male. 



d. Anal vein ends distad of the base of the fork of the cubitus, 

 e. Petiole of media shorter than the crossvein. 

 f. Head and thorax largely fuscous, hypopygium of male 

 much longer than the last visible abdominal segment. 



4. inflata n. sp. 



f f . Head and thorax largely yellowish ; hypopygium 



shorter than last abdominal segment. 5. filipes. 



ee. Petiole of media and crossvein subequal in length ; 



hypopygium small (Fig. 123). 6. imitator n. sp. 



dd. Anal vein ends at or proximad of the base of the fork of 



the cubitus. 



e. Two basal setae on each hind coxa. 7. akeleyi n. sp. 



ee. One basal seta on hind coxa. 



f. Fore tarsi about 3.5 times fore tibia in length in the 



■ male ; 4 scutellar setae. 8. captiosa n. sp. 



ff. Fore tarsi about 3 times fore tibia in length in the 



male; 2 scutellar setse. (Calif.) 9. diffissa n. sp. 



Note. Mycetophila plebeja Walker and M. sericea Say. may belong 



here. 



I. Rhymosia sp. a. 

 Female. Length 3 mm. Head and thorax fuscous, the scape, 

 palpi, humeral spot and thoracic hairs yellow. Abdomen fus- 



