232 DISEASES OF INSECTS. 



mals quit their prey sooner. Reaumur saw a grub of 

 one of the Muscidce come out of a caterpillar, and then 

 become a pupa, which was so large that he wondered 

 how it could have been contained in the animal it had 

 quitted a . 



We have now done with those parasites that produce 

 in insects the disease Ihave called Scolechiasis b : the 

 rest, which belong to the Aptera Order, will afford us 

 examples both of Phthiriasis and Acariasis*. 



I begin with ihejirst. Mv. Sheppard once brought 

 me a specimen of a bird-louse (Nirmus) which he took 

 upon a butterfly ( Vanessa lo) : and should such a capture 

 be more than once repeated, it would afford a certain 

 instance of \hejirst of these diseases amongst insects; but 

 most probably the specimen in question had dropped 

 from some bird upon the butterfly. The only remaining 

 animal belonging to the apterous hexapods that is para- 

 sitic on insects, is by many supposed to be the larva of a 

 giant-beetle (Meloe Proscar abacus). I have before alluded 

 to this animal d , and shall now resume the subject. Gce- 

 dart, Frisch, and De Geer, observed that it deposited in 

 the earth one or two considerable masses, containing an 

 infinite number of very minute orange-coloured eggs 

 adhering to each other, which in about a month were 

 hatched, and produced a number of small hexapods dis- 

 tinguished by two pairs of anal setae and a proleg, by 

 means of which they could move readily upon glass, as I 

 have myself seen : these little animals precisely corre- 

 sponded with one found by the latter author upon Eris- 



1 Reaum. ii. 440 . 



b VOL. I. p. 99. c Ibid. 84, 97. 



' VOL. I. p. 163. note c . VOL. Ill, p. 162. note b . 



