452 The Enemies of the Wheat Fly. 



glumes of the wheat in July and August, when it runs over ther 

 ears and searches out the infected ones, depositing a single agg in 

 each of the larvae by means of its sharp tail. The late Mr. A. 

 Mathews, before he left England, sent me specimens, informing 

 me that he had found them in the greatest abundance in the 

 glumes of the wheat in a field near Sittingbourne, Kent, the be- 

 ginning of July. Never having seen this Ichneumon depositing 

 its eggs, I cannot satisfy the curiosity of the reader better than by 

 transcribing Mr. Kirby's graphic account of its operations. " To 

 see our little Ichneumon,^'' says Mr. Kirby, " deposit its Qgg in the 

 caterpillar of the wheat-fly is a very entertaining sight. In order 

 to enjoy this pleasure I placed a number of the latter upon a sheet 

 of white paper, at no great distance from each other, and then set 

 an Ichneumon down in the midst of them. She began immedi- 

 ately to march about, vibrating her antennae very briskly ; a larva 

 was soon discovered, upon which she fixed herself, the vibratory 

 motion of her antennae increasing to an intense degree : then 

 bending her body obliquely under her breast, she applied her anus 

 to the larva, and during the insertian of her aculeus and the depo- 

 siting of the Qigg her antennae became perfectly still and motion- 

 less. Whilst this operation was performing, the larva appeared to 

 feel a momentary sensation of pain, for it gave a violent wriggle. 

 When all was finished, the little Ichneumon marched off" to seek 

 for a second, which was obliged to undergo the same opera- 

 tion, and so on to as many as it could find in which no agg had 

 been before deposited, for it commits only a single Qgg to each 

 larva. I have seen it frequently mount one which had been 

 pricked before, but it soon discovered its mistake and left it. The 

 size of it is so near that of the Tipula, that I imagine the larva of 

 the latter could not support more than one of the former, and, 

 therefore, instinct directs it to deposit only a single egg in each ; 

 besides, by this means ane Ichneumon will destroy an infinite 

 number of larvae." 



" These parasites are all included in the Order B[tme:;optera, 

 and the Family IcHNEUMONiBES ADSciTi ; the species I am about 

 to describe is comprised in the Genus Platygaster ;* it has been 



* So Darned from some of the larger ones having broad bodiesi 



