BULLETIN No. 196. 



THE MYCETOPHILID^ OF NORTH AMERICA. 

 Part HI.* 



THE MYCETOPHILIN^. 



O. A. JOHANNSEN. 



The Mycetophilinje embrace many genera which resemble 

 each other in possessing an unbranched radial sector and in 

 lacking the M-Cu crossvein.. The subfamily is very probably 

 of polyphyletic origin apparently having arisen for the most 

 part from several Sciophiline genera. It is therefore not a 

 natural group but for practical purposes a very convenient one. 

 In nearly all the genera the anal furrow which simulates a longi- 

 tudinal vein lying immediately behind the cubitus, is present, 

 the first anal vein though frequently strong does' not reach the 

 wing margin in any recent North American form and the sec- 

 ond anal is less distinct or vestigal. 



In all the North American genera there are 2-]- 14 antennal 

 joints except in the genus Cordyla. The middle ocellus which is 

 present in most, is absent in Mycetophila and Cordyla and rare- 

 ly present in Dynatosoma, and Bxcchia. The thorax is high 

 and arched and the abdomen more or less compressed. There is 

 one spur at the apex of each fore tibia and a pair on each of 

 the middle and hind tibiae. The claws have one or more basal 

 teeth. In some BoletincE and Coelosice one claw is peculiarly 

 modified. 



It is evident that there are several natural groups of genera 

 which may be tentatively arranged according to the following 



* Papers from the Maine Agricultural Experiment Station, Ento- 

 mology No. 50. Parts I and TI were published in Bulletins 172 and 

 180 respectively. Where the types of the new species are to be found 

 will be stated in Part IV, now ready for the press. 



