260 INSECT TRANSFORMATIONS. 



Transformations of the wheat fly. a, the female fly magnified ; 

 b, larvae, natural size, feeding; c, one magnified. 



sect is providentially prevented from multiplying so 

 numerously as it might otherwise do, by at least two 

 species of ichneumons, which deposit their e^gs in the 

 larva3. One of these {Encyrtus inserens, Latr.) is 

 very small, black, and shining. The other {Platij- 

 gaster Tipidce, Latr.) is also black, with red feet, and a 

 blunt tail. These have been frequently mistaken for 

 the wheat-fly; but as it has only tico wings, while they 

 have four, the distinction is obvious. In order to 

 observe the proceedings of the ichneumons, Kirby 

 placed a number of the larvre of the wlieat-fly on a 

 sheet of white paper, and set a female ichneumon in 

 the midst of them. She soon pounced upon her vic- 

 tim, and intensely vibrating her antenniB, and bending 

 herself obliquely, plunged her ovipositor into the body 

 of the larva, depositing in it a single egg. She then 

 passed to a second, and proceeded in the same man- 

 ner, depositing a single egg in each. Nay, when 

 she examined one which she found had already been 

 pricked, she always rejected it and passed to another.* 

 Mr Shireft' repeated these experiments successfully, 

 except that he saw an ichneumon twice prick the 

 same maggot, which ' writhed in seeming agony,' 

 and ^ it was again stung three times by the same 

 fly.' He adds, ' the earwig also destroys the larvae, 

 three of which I successfully presented to an earwig, 

 which devoured them immediately.'! ]Mr Gorrie 

 describes these ichneumons as appearing in myriads 



* Linn. Trans, ut supra. + Loudon's Mag. ut supra. 



