AMONG CATERPILLARS 41 



tions, as in the species of Basilarcliia. Others 

 when disturbed strike with their mandibles the leaf 

 upon which they are resting, as the Red Admiral 

 (Vanessa atalanta) and Harris's butterfly (Cincli- 

 dia harrisii) are known to do. Or they may move 

 their heads from side to side, catching their man- 

 dibles in the roughnesses of the leaf, and so pro- 

 duce a grating sound, — a very common trick of 

 the higher Hesperidae. A curious allied habit is 

 found in the Blue Swallow-tail (Laertias philenor), 

 which repeatedly taps alternately with its front 

 legs upon the leaf when disturbed, — a habit I 

 have seen in no other caterpillar. The Monarch 

 (Anosia plexippus) again, which, when eating, 

 keeps its anterior flexible filaments constantly in 

 motion forward and backward, moves them with 

 still greater violence when it is in a state of alarm, 

 and this must serve as a very considerable protec- 

 tion to it. 



Nearly all caterpillars, whether of butterflies or 

 moths, will, when disturbed, throw their heads 

 violently around from side to side in a threatening, 

 angry manner, the head with its hard incasement 

 and biting jaws being the most offensive weapon 

 in the control of the caterpillar. But it is a very 

 curious sight to see how, as impelled by one im- 



