54 THE STUDY OF INSECTS. 



The larval stage is devoted to growth; the sole business 

 of a larva being to eat and grow. All molting, because of in- 

 creased size, is done in the larval stage, later molts are 

 simply for change of shape. 



The Pupa. — This is the third stage in the life of an in- 

 sect, and is ordinarily a period of inaction, except that rapid 

 and wonderful changes go on within the body. Very few 

 pupae, like those of mosquitoes, are active. Usually pupae 



have no power of moving 

 around, but many of them can 

 squirm when disturbed. When 

 the last skin of the larva is 

 thrown off the pupa is re- 

 vealed ; it is an oblong object, 



Fig. 65. — A pupa of a large moth. 1 r _ _.i ,1 



^ v v * and frequently apparently 



headless and footless. In many pupae the skin is a shiny 

 covering like porcelain. If a pupa be examined closely the 

 antennae and legs and wings may be seen ; these are folded 

 up closely and soldered to the breast in the case of the 

 moths and butterflies (Fig. 65), but free in case of the bees, 

 ants, and beetles. 



The Chrysalis. — This term is often applied to the pupa of 

 a butterfly. The word is derived from a Greek word mean- 

 ing gold, and came into use because of the golden dots and 

 markings on many of the butterfly pupae. 



The Cocoon. — Many larvae, especially those of moths, 

 when full grown, spin about the body a silken case, so that 

 when they change to helpless pupae they may be protected 

 from enemies, and from rain and snow ; these silken cases 

 are called cocoons. They are frequently made within a 

 rolled leaves (Fig. 66), or beneath grass and rubbish on the 

 ground, or in cells below the ground. Some hairy caterpil- 

 lars make cocoons largely of their own hairs, which they 

 fasten together with a film of silk. 



The NympJi. — The terms larva and pupa are only ap- 

 plied to the early stages of those insects that have a com- 



