56 . THE BUTTERFLY. 



the base, and differ from the remainder in their 

 greater size ; most of the movements of the anten- 

 nae are due to the freedom of motion of these basal 

 joints ; the stalk is a mere jointed thread, and the 

 club only an enlargement of the final joints, 

 where they lose in length what they gain in thick- 

 ness [Fig. 66] ; the extent and shape of this club 

 vary widely among butterflies and often form a 

 valuable guide to their real relationship. The 

 antennae may be bare or they may 

 be clothed to a greater or less extent 

 with scales similar to those which 

 cover the wings ; but in the latter case 

 there is nearly always a naked space 

 along the under surface, and particu- 

 larly on the club, where it is provid- 

 FIG. 66.-cinb ed with microscopic pits, connecting 



of antenna of Xan- . 



thidia Nicippe, with delicate nerves, which are un- 



X 25. The view 



innS iow f erside he doubtedly organs of sense, but whose 



use is not yet fully understood. 

 Coming next to the mouth-parts of the butterfly, 

 we shall find it difficult to believe that the won- 

 derful apparatus by which the insect now pro- 

 cures its food in the depths of tubular flowers is 

 simply a development of parts already in exist- 

 ence in an earlier stage, when by means of horny 

 jaws it made such havoc among the leaves of 

 its food-plant. The principal mouth-parts are a 

 long, slender, flexible tube, rolled up precisely 



