56 THE BOOK OF THE FLY 



to baffle investigation. Some have now been proved 

 capable and others are suspect of baneful possibilities. 



The house-fly fungus, Empusa musccc, which is pre- 

 valent in autumn, has ever attracted popular wonder 

 and much scientific attention. It has been much 

 written about and plentifully illustrated, but the 

 complete life-cycle of this peculiar parasitic growth 

 is not yet understood ; much that has been published 

 as of fact is mere "copy" repeated in one book after 

 another, originally in fact rather a matter of conjecture, 

 based upon the idea that fungic propagation must be 

 on exactly parallel lines with known biologic processes 

 of a botanic order. 



The house-fly fungus seems to have a superficial 

 resemblance to some of the common "moulds," but 

 mycologically examined there is good reason for 

 classifying it with a family (Entomophthorecv), which 

 may be capable of an alternative form of fructificative 

 development. 



The originating germ somehow at some time must 

 be supposed to have effected a lodgment in the body 

 of the fly or possibly that of the maggot. Later on, 

 one cannot say when, fungic spawn (a pulpous 

 mycelium) starts a course of development, invades 

 every part of the body, quickly kills the fly, and fixes 

 it to the spot to which in its last moments it has 

 crawled, often a window-pane. Its corpse is now 

 swollen with the spawn developed into masses termed 

 hyphal ; but these should not be called hyphal (thread) 

 but quasi-sclerotia, bodies intermediate in a process of 

 normal development between the mycelium and the 

 fruiting stage ; fungic fructification ensues with great 



