246 



PTILOTA: IMAGO EXTERNAL ANATOMY. 



), but which Latreille terms siphunculus. More- 

 over, the mouth of the bee, which is chiefly organized upon 

 the same plan as the biting mouth of the beetle, but has its 



parts elongated so .as to sip up the honey of flowers, is 

 termed by Latreille a promuscis (although that term had 

 been given by Kirby and Spence to the mouth of the bug 

 tribes). 



Throughout this great variation of structure, however, 

 the strictest uniformity is maintained, the same number of 

 parts existing in all, although occasionally rudimental or 

 modified in various degrees, so as to correspond with the 

 functions which they have to support. As, however, these 

 modifications of structure are permanent throughout entire 

 groups, serving, in fact, for the establishment of orders, ac- 

 cording to some authors, it would surely be absurd to deny 

 the propriety of assigning to each variation a distinct and 

 fixed name. 



The mouth of the hexapod winged insects being thus com- 

 posed of a certain number of part?;, may much more easily 



