DISEASES OF INSECTS. 233 



tali's intricarius ,- and when that fly was placed amongst 

 them, they immediately attached themselves to it, so as 

 to leave no doubt of their identity a . A congenerous 

 species had been detected upon wild bees, and described 

 by Linne under the name of Pediculus Apis. De Geer 

 is so thoroughly to be depended upon for his veracity 

 and accuracy of observation, that we cannot suppose 

 there is any incorrectness in his statement. If the mass 

 of eggs be, as he represents it, of the size of a hazel-nut, 

 it must have been the product of a very large insect : 

 in confirmation of this opinion it may be further ob- 

 served, that the larva of the kindred genus Cantharis 

 agrees with it in having anal setae, though it appears to 

 differ in having only two conspicuous segments in the 

 trunk b . Those which infest wild bees make their first 

 appearance upon acrid plants, which the Meloe likewise 

 feeds upon; from whence with wonderful agility they 

 leap upon the Andrence^ &c. that visit these flowers. 

 Strong, however, as all these facts appear, still we cannot 

 help exclaiming with the illustrious Swede last named, 

 Who could ever have imagined that the larva of this 

 great beetle would be found upon the body ofjlies, and 

 we may add, or bees ? Who could ever imagine that it 

 would feed like a bird-louse and resemble it so closely ? 

 that in the insertion of its palpi it should exhibit a cha- 

 racter exclusively belonging to that tribe c ? Another 

 circumstance seems to indicate that these hexapods at the 

 time that they take their station in bees or flies are per- 

 fect insects they do not vary in size, at least not mate- 

 rially. Where, we may also ask, if they are to become 



a De Geer v. 8. 



b Nalurf. xxiii. /. If. 8. c .V. Did. d'Hisi. Nal. xx. 110. 



