HEX A POD A. 



53 



times referred to as the exuvice (ex-u'vi-se). Insects differ 

 greatly as to the number of times they molt : many species 

 molt only four or five times, while others are known to 

 molt more than twenty times. Figure 620. represents the 

 cast skin of a Dragon-fly clinging to a reed. 



The Egg. This is the first stage in the existence of 

 any insect, although in some 

 few instances the egg remains 

 in the body of the mother till 

 it hatches. But almost always 

 the eggs are laid by the mother 

 insect on or near the food which 

 gives nourishment to the young. 

 Many of the most interesting 

 habits of insects are connected 

 with the care of the eggs by 

 the parent. The eggs may have 

 smooth oval shells; but often 

 the shells are beautifully ribbed FIG. 6 3 . Egg of cotton-worm, greatly 



enlarged. (From the Author's Report 



and pitted \rig. 03), and some- on cotton insects.) 



times they are ornamented with spines, and are frequently 



exquisitely colored. 



The Larva. This is the second stage of an insect's life, 

 and is the form that hatches from the egg. Familiar exam- 

 ples of larvae are caterpillars, maggots, and grubs (Fig. 64). 



FIG. 64. A caterpillar, the larva of a moth. 



In fact, nearly all the creatures commonly known as worms 

 are larvae of insects. Away from the ocean we find but few 

 worms, except earthworms, leeches, " hair-snakes," and 

 worm parasites in the intestines of men and animals. 

 Nearly all the rest, except millipedes and centipedes, are 

 larvse of insects, and finally change to forms with wings. 



