VARIOUS FORMS OP MOUTH. 245 



canal of a fleshy or leathery substance, but furnished; inter- 

 nally with several slender bristles, which the insect 'employs 

 as lancets to wound its prey. In the flea again the structure 

 is quite different. 



These insects may be cited as affording examples "of the 

 chief variations which occur in the general structure of the 

 mouth, and to each of which, as a variation of the mouth, a 

 name has been applied. Thus the mouth of the butterfly, 

 and other lepidopterous insects (fig. 87), is termed by Kirby 

 and Spence antliaj by Fabricius lingua (an evidently excep- 

 tionable term, being only strictly applicable to a single organ 

 of the mouth) ; and by Latreille spirignatha. The mouth 

 of the fly (fig. 88) is termed by Kirby and Spence, Linnrcus, 



mi/)' 



Proboscis of Diptera (Tabanus). 



and Fabricius, proboscis. The mouth of the aphides and bugs 

 (fig. 89) is denominated by Kirby and Spence a promuscis- 

 but by Fabricius, Olivier, and Latreille, rostrum, a term more 

 properly applicable to those insects which have the head 

 produced in front into a beak or snout, as the weevils or 

 scorpion-tailed fly (Panorpa), but which latter Latreille, for 

 distinction, terms proboscirostrum. The mouth of the flea 

 is termed a rostrulum by Kirby and Spence, and rostellum 

 by Latreille, the latter name having been proposed by Kirby 

 and Spence for the suctorial organs of the louse tribe (Pe- 



\3 



