APHIS. ] 8-1 



of the insect adhering to the leaf like a small pearl. 

 Such may always be found where Aphides are in 

 plenty. We have observed different species of 

 Aphides to be infested with different Ichneumons. 

 In general the torpid Aphis submits quietly to 

 this fatal operation; but we have observed some 

 of them, especially one that feeds on the Sycamore, 

 which is much more agile than many of this race, 

 endeavouring to avoid the Ichneumon with great 

 address. There is perhaps no genus of insects 

 which in their larva or maggot state feed on such 

 a variety of food as the Musca or Fly. There is 

 scarcely a part of Nature, either animate or in- 

 animate, in which they are not be met with. One 

 division of them, called by Linnaeus Muscce aphi- 

 di-coree, feeds entirely on Aphides. Of the different 

 species of aphidivorous flies, which are numerous, 

 having mostly bodies variegated with transverse 

 stripes, their females may be seen hovering over 

 plants infested with Aphides, among which they 

 deposit their eggs on the surface of the leaf. The 

 larva or maggot produced from such eggs feeds, 

 as soon as hatched, on the younger kinds of Aphis, 

 and as it increases in size, attacks and devours 

 those which are larger. These larvas are usually 

 of a pale colour, adhere closely to the leaf, along 

 which they slowly glide, and are formed very 

 tapering towards the head. When fully grown 

 they change to a pupa or chrysalis attached to 

 the leaf, from whence issues the fly. The larva? 

 of these flies contribute their full share to diminish 

 the despoilers of Flora. To these three kinds of 



