HEXAPODA. 
53 
times referred to as the exuvicz (ex-u'vi-ae). 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 62 a 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 arc 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 f.o.^e^oI c^n-wo™, 
and pitted (Fig. 63), 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 larva; 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 
larvae of insects, and finally change to forms with wings. 
