214 MxMNE AGRICULTURAL EXPERIMENT STATION. IQOQ. 



terms in the designation of the various appendages. FoUowing 

 Dziedzicki and Lundstrom I shall call the upper and lower 

 lateral appendages respectively the upper and lower forceps ; 

 when the homology seems evident I shall use the terms eighth 

 and ninth tergum and sternum as given by Snodgrass ('04), 

 otherwise shall speak of these appendages as the dorsal and 

 ventral sclerites. Sometimes, when one or the other of the 

 lateral appendages are wanting or greatly reduced the remain- 

 ing pair will be simply designated as the forceps. When there 

 are appendages of sternum and tergum which require designa- 

 tion they will be called respectively sternal and tergal processes 

 or lobes. 



Habits and Economic Relations. 



As far as known most of the members of this family live 

 upon and destroy mushrooms, not only the wild plants but on 

 occasion the cultivated varieties as well. ]\Iany a mushroom 

 though apparently sound, will, upon close scrutiny reveal tiny 

 black headed larvae which within a few days grow to maturity 

 and if numerous completely riddle the plant. If left upon the 

 earth the larvze when full grown will bury themselves, pupate, 

 and within a short time emerge as adults. While but few 

 references to the higher fungus gnats (Mycetophilincu) are 

 found in economic literature, nevertheless I may say from per- 

 sonal observation that a large percentage of the wild mush- 

 rooms are infested with the larvse of Mycetophilince, particu- 

 larly of the genera Exechia and Mycctophila, and in several 

 instances have found them in company with the larvae of PJiora 

 to utterly ruin a mushroom bed in the cellar of a grower. 



The larvse of Mycetobia live upon decaying wood, particu- 

 larly of the apple or peach tree, though probably without injury 

 to the sound wood. The Ceroplatincc and Sciophilincr as far 

 as known live upon fungi and decaying wood. As they are 

 comparatively rare they are not likely to be of economic impor- 

 tance. The Sciarincc on the other hand are frequently men- 

 tioned by economic entomologists. Though often found in 

 decaying mushrooms and in the earth in putrid vegetable mat- 

 ter I have never found them to be injurious to growing fungi. 

 They are frequently present, feeding on potatoes afifected by 

 scab or rot, in some apparently well authenticated instances 



