58 J. PERCY BAUMBERGER 



EXTENT OF MYCETOPHAGY AMONG IN8ECT8 



As a corollary to the foregoing conclusions we may assume that 

 the foods of many insect larvae feeding on dead, decaying, and 

 fermenting vegetable and animal matter are the micoorganisms 

 which live upon the substratum in which the insects are embedded. 



The extent of this habit among insects is very great, includ- 

 ing a large number of Coleoptera and an especially large 

 number of Diptera. This habit is usually apparent from the 

 habitats selected by the insect, thus Metcalf ('16) lists the 

 following habitats for the scavenger short- and long-tailed filth 

 larvae of the flower-fly (Syrphidae), viz.: In decaying parts of 

 trees and herbaceous plants, diseased or flowing sap, heaps of turf 

 or soft mud containing vegetable matter, and in stagnant or 

 putrid water, sewage, manure, or himian feces. The larvae also 

 occur as accidental body parasites, .causing intestinal, nasal, auric- 

 ular, and vaginal myasis. Some species serve as scavengers in 

 the nests of termites, ants, wasps, and bees. It is apparent 

 that microorganisms abound in all these environments, with the 

 possible exception of the animal body In the latter case, how- 

 ever, it is well known that a foul odor, indicating some bacterial 

 action, always precedes infestation. In more normal habitats 

 the microorganisms so completely outweigh the other nutritive 

 materials that it is quite likely they (the bacteria) serve as food.'-^ 



Townsend ('93) lists the following habitats for some of the scav- 

 enger Acalyptrate muscid larvae : dung, decaying wood, under 

 bark, plants, leaves, roots, tubers, and fungi; in salt or alkaline 

 water and mud; urine, vinegar, sap of wounded trees; cheese and 

 animal fats. Again in this case all habitats selected by the fly 

 normally abound in microorganisms, and it is quite safe to assume 

 that they (the fungi) serve as food for the insect larvae. 



The great extent of the use of microorganisms as food among 

 insects is shown in a table of the feeding liabits of larval and adult 

 Diptera. In this table I have assumed that the food of insects, 

 that always inhabit substrata of a fermenting or decaying nature, 



-' Osborne and Mendel ('I Ij showed thai the bacterial content of feces was 20 

 to 40 per cent. 



