INTRODUCTION. 27 
Hymenoptera and Neuroptera, although one would not think so 
from their appearance. In conclusion, if an insect’s power of 
flying is not considerable, its power of traction and propulsion are 
immense, compared with the vertebrate animals; and, in the same 
group of insects, those that are the smallest and lightest are 
the strongest. The proportion between the muscular strength of 
insects and the dimensions of their bodies, would not appear 
to be on account of their muscles being more numerous than 
those of vertebrate animals, but on account of greater intrinsic 
energy and muscular activity. The articulations of insects may 
be considered as solid cases which envelop the muscles, and 
the thickness of these cases appears to decrease in a singular 
manner according to the size of the creature. The relative 
bulk of the muscles being less in the smaller species than in the 
larger, it is necessary to explain the superior relative strength of 
the former by supposing them to possess a greater amount of vital 
energy. 
These astonishing phenomena will perhaps be better under- 
stood if we consider the obstacles which insects have to overcome 
to satisfy their wants, to seek their food, to defend themselves 
against their enemies, &c. 
To meet these requirements they are marvellously constructed 
for both labour and warfare, and their strength is superior to that. 
displayed by all other animals. It is also much greater than that of 
the machines we construct to replace manual labour. They repre- 
sent strength itself. God’s workmen are infinitely more powerful 
than those invented by the genius of man, which we call machines. 
We think it necessary, in closing this chapter, to give a sort of 
general outline of the great class of animals which we are about to 
study. If we wished to characterise insects by their exterior 
aspect we might consider them as articulate animals, whose 
bodies, covered with tough and membranous integuments, are 
divided into three distinct parts: the head, provided with two 
antenne, and eyes and mouth of very variable form; a trunk or 
thorax, composed of three segments, which has underneath it 
always six articulated limbs, and often above it two or four wings; 
and an abdomen, composed of nine segments, although some 
may not appear to exist at first sight. 
