STRUCTURES IMPLICATED IN METAMORPHOSIS. 



J3 



and the body ends in a tubercle. Their consistence is the same 

 throughout, and the constituent membrane is almost homoge- 

 neous. The third, fourth, fifth, sixth, and the ninth segments of 

 the abdomen have a pair of tubercles furnished with spines on 

 their underneath or ventral surface. These tubercles, which are 

 destined to disappear when the insect passes into the chrysalis 



LARVA, OR CATERPILLAR. 



ADULT FORM, OR MOTH. 



The same insect, Attacus pavonia major, in the larval and adult stage, seen front 



underneath. 



condition, act as legs. They are not true legs, but only prolon- 

 gations of the skin ; but they are used as holders and locomotive 

 organs, and under the term of membranous feet or legs are 

 invariably present in caterpillars. 



Now compare the abdomen of the moth with that of the 

 caterpillar. 



The number of the segments is no longer the same, and only 

 5even can be counted. The first has joined itself to the chest-piece 



