26 



NATURAL HISTORY OF INSECTS. 



the pupse of many Butterflies, such as those represented in 

 Figs. 74 and 75. The pupse of many kinds of Two- winged 

 Flies are enclosed in the old larva-skin, which becomes con- 

 tracted and hardened (Fig. 76). Pupae of this kind are said 

 to be coarctate or compact, while the others mentioned above 

 are said to be obtected or covered. 



No insect can produce eggs or bring forth living young while 

 in the pupa state; it is only in the perfect or adult state that 

 insects can reproduce their kind. (See Note, p. 23.) 



CHAPTER V. 



THE TRANSFORMATIONS OF INSECTS. 



Insects, with but few exceptions, pass through the four 

 stages corresponding to the egg, the larva, the pupa, and the 

 imago state. 



These different stages are easily observed in the development of 

 the Archippus Butterfly. From the egg (Fig. 77, c, natural size; 

 a magnified), is hatched a small worm-like creature, the larva 

 (Latin larva, a mask); so named, because "masking," as it 

 were, the perfect insect. This at once begins to feed upon the 



Fig. 77. 



leaves of the plant upon which the egg had been deposited by 

 the parent butterfly; after increasing somewhat in size it casts 

 off its old skin, and appears in a new and more commodious 

 one. This process is termed "moulting." 



When this time for moulting arrives, the caterpillar first 



