INSECTS. 171 



the moisture evaporates from the skin ; the texture 

 becomes firm ; the colours appear in their perfect 

 beauty, and the wings expand to their full size. 



Butterflies, in common with all other insects, are 

 furnished with antennae, which is the name given to 

 those long horn-like organs which arise from each 

 side of the head ; but to what common use, or want 

 of the insect kind, a provision so universal is sub- 

 servient, has not yet been clearly ascertained. They 

 have been regarded by some as organs of smell, by 

 others as organs of touch, but though they may be 

 used occasionally as organs of touch, this is neither 

 their general nor their primary use, for the antennae of 

 very great numbers never are nor can be employed 

 for this purpose. Lehmann considers it to be most 

 probable that they are the organs of a sense not 

 perfectly analogous to any of ours, but coming near- 

 est to that of hearing ; for they certainly collect 

 notices from the atmosphere. This unknown sense 

 he calls aeroscepsy. 



An extraordinary instance of irritability is exhibi- 

 ted by the antlia (tongue, or instrument of suction) 

 of the butterfly. If this organ, which the insect can 

 roll up spirally like a watch spring, or extend in a 

 straight direction, be cut oft', as soon as the animal is 

 disclosed from the chrysalis, it will continue to roll 

 up or unroll itself as if still attached to the head : 

 and if, after having apparently ceased to move for 

 three or four hours, it be merely touched, it will 

 again begin to move and resume the same action, this 

 is doubtless occasioned by the peculiar structure of 

 the antlia, which is composed of numerous horny 

 rings, acted upon by muscles, more numerous, pro- 

 bably, than those which compose the trunk of the 

 elephant. The motion only ceases when the mus- 

 cles become dry and rigid. 



The larvae of butterflies are universally known by 

 the name of caterpillars. The body of the caterpillar 

 when anatomically considered, is found composed t)f 

 rings whose circumference is nearly circuhir : they 



