MOTHS AND BUTTERFLIES. 189 



of vision, it is more than probable that they are pro- 

 vided with eyes : for if we examine them with a mag- 

 nifying glass we discover on each side of the head six 

 black jpots in a circle, which seem to answer the or- 

 gan of sight, and if we approach them in the night 

 with a light, they immediately begin to move, which 

 shows that they must have some means of being af- 

 fected by the light. Besides, their motions in various 

 voluntary directions, testify much in favor of such an 

 opinion, although it is possible that these may be de- 

 tected by their exqusite sense of smell. 



There is no caterpillar which does not spin a web of 

 some kind, by issuing a thread from a fleshy point of 

 the under lip. 



Body. — The body of a caterpillar consists of twelve 

 ringlets, upon nine of which, on each side of the ven- 

 tral portion of the body, is . seen an oval spot, sur- 

 rounded sometimes with a red or yellow ring. These 

 oval spots are the respiratory organs by which the in- 

 sect breathes. That these are the real respiratory or- 

 gans is proved by putting oil or any greasy substance 

 over these air-holes, the consequence of which will be 

 immediate death by suffocation. Moreover, if a cat- 

 erpillar is put under water or alcohol, air-bubbles will 

 be seen issuing from innumerable minute holes, in all 

 parts of its body, and when the skin is taken off from 

 the insect and held up against the light, the holes may 



