BULLETIN No. 172. 



THE MYCETOPHILID^ OF NORTH AMERICA. 



Part L* 

 o. a. johannsen. 



It is the purpose of this paper to present a synopsis of the 

 fungus gnats or Mycetofhilidce of North America, giving 

 descriptions of and tables to all the genera and species, and life 

 histories when known. As these flies are for the most part 

 quite small, inconspicuous in coloring and retiring in habit, it 

 is not strange that they, with the exception of a few species 

 which have been brought into prominence by reason of their 

 economic importance, have received but scant attention from 

 entomologists generally. In this, the first part, the lower and 

 economically less important subfamilies are treated, while in a 

 subsequent paper the Sciophiliiice, Mycetophilincs and the 

 Sciarince will be considered. I hope to be able to show, in my 

 work on the Sciarince, just what relation the larvae of Sciara 

 which are so frequently and usually so numerously present in 

 rich soil, bear to the plants which grow there. I also trust that 

 the descriptions of the imagines of the members of this genus 

 will be sufficiently characteristic so that neither the Economic 

 Entomologist nor the Systematist need so often designate a 

 species as Sciara sp. as has been the case heretofore. 



Acknowledgments. 

 To the members of the Entomological Staff of Cornell Uni- 

 versity for their kindness in granting me the freedom of their 

 laboratories, library, and collections I wish to express my 



*Papers from the Maine Agriculture E.xperiment Station : Ento- 

 mology No. 38. 



