The Enemies of the Wheat Fly. 451 



•stalk until it arrives at the joint, where it becomes fixed, and is 

 nourished by the veget:ible fluids that otherwise would have in- 

 vigorated the plant. The loheat midge, a second species, selects the 

 flower as it is only on the grain that her future progeny can sub- 

 sist. And she so manages with respect to the time, that just at 

 the moment when her young ones are sufficiently advanced to 

 require food, the grain of wheat is sufficiently grown to feed them. 



With these two species, the larvae subsist upon vegetable food, 

 but there are others whose organization is such, that they can only 

 live upon animal substances. Consequently such are sought out 

 by the parent ; one kind selecting a dead and another a living 

 animal in which to deposit the agg. Others construct a nest, lay 

 the eggy then sally forth, kill some other insect and place the car- 

 cass in the nest, where it will be ready for the larva to feed upon 

 as soon as the shell is broken. 



It is said by ornothologists, that certain birds too indolent to 

 construct nests of their own, leave their eggs in those of other 

 species, where they are hatched by the unwittingly bestowed 

 warmth of the strangers. Insects are still more unprincipled. 

 The Ichneumon actually waits until the wheat midge has laid her 

 ^gg and until the larva is hatched, when she seizes upon the 

 youthful destroyer of the staff of life, bores a hole through his 

 .skin and deposits her Qgg in the soft parts of his body. The 

 young wheat midge is thus compelled much against his will it 

 appears to become a sort of external step mother to the young 

 Ichneumon, who is hatched inside, and immediately devours his 

 foster parent. 



In was for this reason that the Ichneumon was supposed, at one 

 time, to be the insect that injured the wheat, because they were 

 seen to come out of the empty pupa cases of the wheat fly, when 

 in fact, instead of being injurious it is the most important pro- 

 tector, as its own existence depends upon the destruction of the 

 species which really effects the damage. 



We do not know that the two species of insects described in 

 what follows occur in this country, but as everything bearing upon 

 the principle subject, that of the natural history of insects injurious 

 to our crops is of importance, we think it will be useful to publish 

 the account of them given in the Journal of the Royal Agri^ 

 CULTURAL Society of England, Vol. 6, by John Curtis, f. l. s. 



Referring to the Ichneumon this author says : 



" This insect is found upon grasses as early as June, and on the 



