74 J. PERCY BAUMBERGEK 



wood shows clearly that these Arthropods also feed on micro- 

 organisms, I have also endeavored to account for the origin 

 and devolopment of this habit, to ascertain the probable extent 

 of its occurrence, and to consider the known associations of 

 animals with fungi in general. The experiments and consider- 

 ations all tend to establish the principle that insects inhabiting 

 fermenting and decaying substrata of low protein content, 

 usually feed upon the microorganisms present and thus benefit 

 by the power of the fungi to extract, adsorb, and synthesize 

 many non-protein nitro'genous compounds. 



