32 



CONNECTICUT GEOL. AND NAT. HIST. SURVEY. 



[Bull. 



in Connecticut insects as regards the time required for the eggs 

 to hatch. Many species pass the winter in the egg stage. 



The larva is the stage during which the insect feeds and if- 

 creases in size, casting its skin, or molting, from time to time. 

 The larva of a moth or butterfly is commonly called a caterpillar, 

 that of a fly is known as a maggot, and that of a beetle is often 

 called a grub. It is in this stage that most of the damage is 

 done by insects. Few insects require more than a year in this 

 stage, most of them but a few weeks, and some only a few 

 days or hours. A number of species winter as larvae. 



Fig. 3. Egg-mass of Tent Caterpillar on apple twig. Natural size. 



The pupa, called chrysalis in the butterflies and moths, is 

 the quiescent or non-active stage assumed by the larva when 

 fully grown. The tissues inside break down almost completely 

 to a homogeneous mass of protoplasm, and from this the 

 various parts of the adult, beginning with the head and brain, 

 are formed. The insect thus emerging is entirely different 

 from both larva and pupa, a state of affairs not occurring so 

 markedly in any animals outside of the insects. A large num- 

 ber of species pass the winter in this stage, but some of the 

 flies require but a few hours or days in the pupa stage. Some- 

 times the pupa is naked, but often a cocoon of silk threads is 



