218 EENEST WARREN. 



a general tendency to become parasitic^ and it would then 

 be a matter for conjecture as to the modifications which 

 would thereby be ultimately induced in the species, or that 

 the larvfB have an extraordinary power of adapting them- 

 selves to various environments, so that they are indiiferent 

 whether they live in the alimentary canal of a mammal or 

 on ordinary decomposing animal matter. 



