66 INSECT TRANSFORMATIONS. 



It is not common, however, for the ichneumon 

 flies to deposit their eggs in the bodies of perfect 

 insects, as in most cases they prefer the eggs, larvae, 

 or pupae; but instances are on record of their grubs 

 having been found in the former. The troublesome 

 cock-roach (Blatta) is selected by a parasite fly 

 (Evania apendigaster, FABR.), as remarkable in 

 form as it is rare in occurrence, in Britain at least. 

 It has been found in the vicinity of London; but, 

 were it abundant, it might tend to reduce the num- 

 bers of these black beetles, as they are incorrectly 

 termed, the pests of the kitchen. 



Magnified view of a parasite fly (Evania apendigaster). 



An insect parasite, still more singular in form, 

 and of still rarer occurrence, was discovered by 

 Kirby, above thirty years ago, on the black bronze 

 bee (Jlndrena nigrocenea, STEPHENS). ' I had pre- 

 viously,' he remarks, more than once observed 

 upon other species something that I took to be a kind 

 of Jlcarus which appeared to be immovably fixed 

 just at the inosculations of the dorsal segments of the 

 abdomen. At length, finding three or four upon a 

 specimen of this bee, I determined not to lose the 

 opportunity of taking one off to examine and de- 

 scribe; but what was my astonishment, when, upon 

 my attempting to disengage it with a pin, I drew 

 forth from the body of the bee a white fleshy larva, 



