INTRODUCTION. 27 



Hymenoptera and Neuroptera, although one would not think so 

 from their appearance. In conclusion, if an insect's power of fly- 

 ing 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 membraneous integuments, are 

 divided into three distinct parts : the head, provided with two 

 antennae, 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. 



