FUNGUS GNATS OF XORTH AMERICA. 89 



Auxiliary table to Species of Mycetophila sens. lat. 

 The species included in this table I cannot recognize. Some of them 

 do not appear to belong to the genus Mycetophila as now restricted, 

 a. Wing with one or more spots. 



b. With a single spot which covers the crossvein. 



c. Head blackish, disk of thorax with 3 confluent blackish vittse. 



44. discoidea. 

 cc. Head and thorax clay yellow. 45. ichneumonea. 



bb. With 2 wing spots. 



c. Head and thorax black; length 5 mm. 46. bifasciata 



cc. Head and thorax yellowish to brown. 



d. Length 2.5 mm ; abdomen reddish brown. 47. parva. 



dd. Length 3 mm or over; abdomen reddish brown, segments 

 with yellow margins, 

 e. Preapical wing cloud broader but little longer than the 

 central spot; halteres yellaw ; length 4 mm. 



ZZ- propinqua. 

 ee. Preapical wing cloud much larger than the other, 

 f. Halteres white ; head brown ; length 3.5 mm. 



48. laeta. 

 ff. Halteres and head tawny; length 3 mm. 49. contigua. 

 aa. \. ing iinspolled. 



b. Head black, thorax tawny with 3 broad black stripes, abdomen 

 wantirg. 50. plebeia. 



bb. Otherwise. 



c. Body brown, thorax with tawny stripe "forked in front on 

 its hinder part,'' scutellura and breast yellow, abdomina' 

 segments ye41ow at base. 51. ohscnra. 



cc. Abdominal segments yellow at apex. 



d. Head brown, thorax ferruginous, reddish brown on disk. 



52. despecta 

 dd. Head and mesonotum dusky, (Allodia?). 



e. Halteres whitish, knob dusky before the tip. 53. nubila. 

 ee. Halteres yellowish white. 54. sericen. 



I. Mycetophila exstincta Loew. 



Berlin Ent. Zeitschr. XIII. 152. 1869. 

 Female. Length 2.5 mm. Head fuscous, opaque, the face 

 and mouth parts 3'ellowish. Scape yellow, flagellum blackish, 

 its base sometimes yellow. Thorax fuscous, subopaque, humeri 

 and posterior angle, luteous. Scutellum wholly fuscous black. 

 The first 5 abdominal segments fuscous, the venter and apex 

 of the abdomen yellows Coxse and legs pale yellow, the tip of 

 the hind femora fuscous, tarsi subfuscous, middle tibiae with 3 

 setae on flexor surface, tarsi slender, the hind metatarsus sub- 

 equal in length to the remaining^ joints ; wing vems luteous 



