INSECTS. 
5 
aspect, and sometimes green. The circulation of 
the blood is particularly conspicuous in Spiders, 
and in some species of Cimex or Bug, in which 
the vibrations and contractions of the arteries 
may also be distinctly observed*. 
The first state in which Insects appear is that 
of an ovum or egg. This relates to the generality 
of Insects; for there are some few examples of vi- 
viparous Insects, as in the genus Aphis, Musca,&:c. 
From the egg is hatched the insect in its second 
or caterpillar state, (though the term Caterpillar 
relates more particularly to the insects of one 
peculiar tribe.) This second state has been gene- 
rally known by the name of Eruca, but Linnaeus 
has changed it to that of Lai'xa^ considering it as 
a sort of masked form or disguise of the Insect in 
its complete state. The Larva3 or Caterpillars of 
insects differ very much from each other, accord- 
ing to the different tribes to which they belong. 
Those of the Butterfly and Moth tribe are gene- 
rally and emphatically known by the name of 
Caterpillars, and are universally known. Those 
of the Beetle tribe, except such as inhabit the 
waters, are of a thick, clumsy form, and the abdo- 
men is commonly of a heavy or bulging appear- 
ance. The Larvae of the Locust or Grasshopper 
tribe, and of some others of the same order, do 
not differ much in appearance from the complete 
Insect, except in being destitute of wings. The 
LarVt© of Flies, Bees, and many others, are gene- 
* Especially in the Cimex lectularius or common bug. 
