164 



COLEOPTERA. 



feet that are scarcely perceptible or are entirely foot- 

 less, and most have sharp teeth admirably fitted for 

 boring into hard wood. They live from one to three or 

 more years in the trunks of trees, then make cocoons 

 of chips and pass into the pupa state. Fig. 117, b, is 

 the pupa of Clytus. 



CURCULIONID.E. 



The weevils (Fig. 118, r, Ithycerus noveboracensis, 

 Forster) have the head extended 

 into a stiff proboscis, which is 

 used in feeding,' and which in 

 the female takes upon itself the 

 additional work of an ovipositor, 

 boring holes in wood, nuts, 



etc., 

 (Fig 



gram 

 eggs 

 sides of 

 antennae. 



for the reception of 

 118, a). On the 

 the proboscis are the 

 and at its end are 



the small, biting mouth parts. 

 Examples of this kind, where 

 one organ performs the function 

 of another, are by no means un- 

 common. It is usually an error 

 to assume that any organ has 

 always had the same kind of 

 work to do, or even that it performs the same common 

 function in the same way in all of the living represent- 

 atives of any large group of animals, because we find 

 it doing this work in the same way in all the species 

 that we may happen to know. The vertical motion of 



