OF INVERTEBRATE ANIMALS. 
135 
upon his carcase. The structure of these game-nets is very beautiful. They 
are mathematically exact in their proportions ; and so well does the Spider know 
their construction, that it can walk over every part with the greatest ease, whilst 
the smallest insect in attempting the same is inextricably caught. 
The Swimmers are adapted for plunder in the deep; they are the pirates of the 
insect tribe. They are so constructed that they can walk upon the surface of the 
water, and there are probably few persons who have not observed them pur¬ 
suing their prey over the smooth surface of a pond or lake> on a calm summer’s 
evening. But some spread their nets at the bottoms of ponds and lakes, in the 
middle of which they reside, in a little cocoon. Now as these animals are 
naturally air-breathers, one would wonder how they could live in water. But 
this is provided for by the little animal being enabled to carry down with it a 
supply of air; this it does a little at a time, till it has accumulated sufficient to 
last it for a day or two, when it retires to its habitation to watch for its prey. 
The water Spider was, then, actually making use of the principle on which 
the diving-bell is constructed, ages before Man had thought of employing this 
instrument. 
Among the other animals that occupy the tribe of Arachnidans, we find the 
singular family of Scorpions; also that very prolific family of little animals known 
by the name of Mites. The last are found in almost every possible situation, 
and are the pests of other living animals. Several in foreign countries inflict 
very severe wounds, often attended by fatal consequences; whilst in our own 
country a very disagreeable and common cutaneous disease is the result of their 
attacks. 
The true insect tribe next claims our attention; but their forms and habits are 
so numerous that selection becomes a difficulty, and the more so as the object of 
these remarks is merely to point out how much there is interesting and deserving 
notice in every department of the animal kingdom. But before enumerating the 
orders into which this class is divided we will just glance at the general structure 
and economy of insects. They are characterised by having six legs, a head 
distinct from their body, possessing two antennae or horns, in every part of their 
bodies, they are supplied with little pores leading to tracheae, which are the 
means by which they breathe. They are all produced from eggs. 
One of the most remarkable points with regard to insects is the metamorphosis 
that many of them undergo in the process of their growth. The egg state is the 
first in which we observe them. These eggs are deposited by the parent with 
the most scrupulous attention to the wants of the young offspring directly they 
are hatched ; and thus it is that we find them in all situations. The common 
White Butterfly deposits her eggs on the Cabbage-leaf, which is the food best 
adapted to her young, as the gardener too often wofully experiences. Not only 
