260 INSECT TRANSFORMATIONS. 



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

 6, 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 eggs in the 

 larvae. One of these (Encyrtus inserens, LATR.) is 

 very small, black, and shining. The other (Platy- 

 gaster Tipulce, 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 iwo wings, while they 

 have four, the distinction is obvious. In order to 

 observe the proceedings of the ichneumons, Kirby 

 placed a number of the larvae of the wheat-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 antennae, 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 ShirefF 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. t London's Mag. ut supra. 



