228 DISEASES OF INSECTS. 



site attached to it, which keeps it in check. The only 

 other Dipterous insects that I have seen mentioned as 

 affording pabulum to an Ichneumon, are one of the 

 aphidivorous flies mentioned by De Geer, who does not 

 note the species, to the larva of which the Ichneumon 

 commits only a single egg, producing a grub that intirely 

 devours its interior a ; and two described by Scopoli, 

 one, the larva of ajfa/ frequenting hemp ; and the other, 

 which feeds on a Boletus, that of a gnat b . 



The Lepidoptera, however, is the Order over the larvae 

 of which the Ichneumons reign with undisputed sway ; 

 attacking all indiscriminately, from the minute one that 

 forms its labyrinth within the thickness of a leaf, to the 

 giant caterpillar of the hawk-moth. The most useful of 

 all, however, the silkworm, appears at least with us, ex- 

 empted from this scourge. De Geer, out of fifteen larvae 

 that were mining between the two cuticles of a rose-leaf, 

 belonging to the first tribe here alluded to, found that 

 fourteen were destroyed by one of these parasites, only 

 one coming forth to display itself in all its brilliancy and 

 miniature magnificence c . One of the most useful to us 

 is that which destroys the clothes-moth, which the same 

 writer also traced d . Another, equally serviceable, takes 

 up its abode in the caterpillar that ravages our cabbages 



tion was printed, Say's account of the Hessian Fly has been met 

 with, where he distinguishes it by the above name. (Journal of the 

 Acad. of Nat. Sciences of Philadelphia 181 7.) The Ichnedmon he 

 calls Ceraphron Destructor. 



a De Geer, i. 605. This, as before observed, is not the I. Mus- 

 carum of Linne ; but it ought to have that name, and the other in- 

 stead to be named, /. CoccinellcE. 



* Ent. Cam. 760, 761. 



c De Geer i. 587. 



d Ibid. ii. 876. 



