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- 

 leopterous 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 a . 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 1 '. 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 county 

 perhaps in towns, where the cock-roach abounds, it may 

 be more common. 



8 De Geer, i. 583. ii. 822. 907. 

 b Reaum. vi, 312. 



