THE BUTTERFLY. 



63 



scales and hairs, forming a bristling guard on 

 either side of the face [see Fig. 65]. The size and 

 relations of the different joints vary considerably 

 in different groups ; they may all be very small 

 and look as if they were merely the scaly cover- 

 ing of the front of the face, or they may pro- 



p.m ._ 



FIG. 71. Interior view of the bottom of the head of Danais Plexippus to show 

 the top of the pharyngeal sac and the muscles which distend it, X 16 ; cl, 

 clypens ; cor, cornea of the eye ; oe, oesophagus ; the muscles are : fm, the 

 frontal ; dm,, the dorsal, and Im, the lateral ; pm, muscles moving the palpus 

 (Burgess). 



ject straight forward with a threatening aspect 

 almost as far as the antennae. 



We pass now to the middle region of the body, 

 the thorax. Here the first segment, or prothorax, 

 is reduced to a most insignificant part, and the 

 only wonder is that it is capable of .supporting a 



