2 A BOOK OF INSECTS 



still larger number, and as none of these creatures has 

 any sign of wings, we are able at once to deny them the 

 proud name of insect. 



Insects are a dominant race, and the secret of their 

 success rests with their peculiar fitness for the life which 

 they lead. Regarded as a machine, an insect is more 

 cunningly designed, more perfectly equipped, than any 

 other invertebrate type. Just as man is chief of the 

 animals with backbones, the most successful example that 

 the world has yet seen, so insects are the leading race of 

 the invertebrate class. We shall do well to fix firmly in 

 our minds that an insect is planned quite differently from 

 such animals as rabbits, birds, and fishes. It possesses no 

 internal skeleton, but its skin is permeated with a peculiar 

 substance called chitin (the " ch " is pronounced like " k "), 

 which is remarkably hard and durable, and is unaffected 

 by almost all ordinary acids and alkalies. It is, in fact, 

 well calculated to resist the weather, and to sustain the 

 wear and tear of an active life. Thus, for practical pur- 

 poses, we may regard an adult insect as living within a suit 

 of strong, light armour, to the inner walls of which its 

 muscles are attached to give them the leverage necessary 

 for their play. This suit of armour is divided into three 

 compartments. The first encases the head ; the second, 

 from which spring the six legs and the wings, protects the 

 chest or thorax ; while the third envelops the hind-body 

 or abdomen. 



Like the children of Esau, insects are essentially a 

 hairy race. Hairs long and short, differing widely in 

 form, are found on all parts of their bodies. These fre- 

 quently determine the colour of an insect, and constitute 

 its chief ornament. The humble-bee, for example, has 

 its body banded alternately with orange and black hairs, 

 while the so-called scales of a butterfly's wings are really 



