DISEASES OF INSECTS. 223 
that do not close, and toothed at the end, usually at- 
tends masses of dung, both of man and cattle, probably 
for the purpose of depositing its eggs in some of the Co- 
leojJterous larvae that inhabit it. Mr. Stephens, one of 
the most accurate observers as well as one of the best 
Entomologists of the present day, informs me that he 
once captured three specimens of Timarcha tenebricosa, 
from each of which forty or fifty minute Ichneumons 
emerged. An insect also of this Order, that is a great 
benefactor to mankind, as a destroyer of the plant-lice, 
— I mean the lady-bird (Coccinella), in its larva state is 
itself subject to the attack, as we learn from De Geer, 
of one of these small parasites*. He detected them also 
in that of two species of weevils : and in the pupa of 
some large grub of a beetle inhabiting the wood of the 
elm, perhaps that of the stag-beetle, he found the pupa 
of one of those Ichneumons that have an exserted ovi- 
positor 6 . Doubtless, did we know their history, we 
should find that numberless species have their internal 
assailants belonging to this tribe. 
Orthopterous larvae seem not to have been yet an- 
nounced as affording a pabulum to these animals : but 
the late Dr. Arnold, whose tact for observation with re- 
gard to the manners and economy of insects has rendered 
his loss irreparable, discovered that the remarkable 
parasitic genus Evania was appropriated to the all- 
devouring Blatta. Whether it attacked it in its egg or 
larva state I have not been informed. This little bene- 
factor is here extremely rare, at least in the countiy ; 
perhaps in towns, where the cock-roach abounds, it may 
be more common. 
a De Geer, i. 583—. ii. 822—. 907. 
b Reaum. vi. 312. 
