MYCETOPHIUD^E. I35 



less density, spun by the larvae; others enclose them- 

 selves in earthy cases. 



The study of the mature insect requires some care. 

 Usually a compound microscope is necessary for the de- 

 tection of many characters, especially of the more minute 

 species, and generally, when there is doubt of the iden- 

 tity, it is best to mount the whole insect or the most im- 

 portant parts under a cover glass. 



In America, as elsewhere, but little study has been 

 given to this family, and hence there are doubtless not 

 a few genera that have hitherto escaped detection. The 

 following table has been for the most part compiled from 

 V. d. Wulp, Winnertz and Schiner, and compared with 

 representatives of nearly all the genera. 



TABLE OF GENERA, 

 i. Coxae moderately long; anterior cross-vein in the same right line 

 with the second section of the third vein; the fifth vein forked 



near base of wing Sciarinae. 



Coxae much elongated; anterior cross-vein distinctly angulated 

 from the second section of the third vein. ... 2 



2. Only the distal part of the forks of the fourth vein visible. . 3 

 Fourth vein visible in its whole extent, the anterior fork rarely in- 

 complete proxitnally. ........ 4 



3. Probosois short; palpi three-jointed; ocelli distinct (1). Manota. 

 Proboscis much elongated; no palpi; ocelli indistinct or absent 



(2,3) Probolaeus. 



4. Origin of fourth vein from the fifth, near base of wing; sixth vein 



more or less indistinct. ....... 5 



Origin of fourth vein opposite or beyond the origin of the third; 

 sixth vein usually distinct. ...... 6 



5. Third longitudinal vein furcate, its anterior branch* usually so near 



its origin and so transverse in position that it resembles a super- 

 numerary cross-vein; three ocelli present. Sciophilinae. 

 Third longitudinal vein not furcate. . . Mycetophilinae. 



* In reality the second longitudinal vein. 



