USEFUL INSECTS 197 



animals with which we have formed a friendly association. 

 Moreover, the type of life of the creatures in a way excludes 

 them from any kind of share in human society. Each of 

 them is, from its birth to its death, entirely devoted to the 

 interests of its little commonwealth. Every impulse of their 

 being relates to the economy of their hive. While we know 

 little about instinct, we know enough of its manifestations to 

 state that the real unit of this species is not the individual 

 insect, but the colony to which it belongs. The separate 

 form is hardly more than a bit of machinery so arranged that 

 it may operate at a distance from the engine of which it 

 forms a part. On this account it appears to be impossible 

 for us ever to attain to any kind of sympathetic relations 

 with these creatures. 



Even more important than the bees are those insects 

 which, in their immature state, yield us silk. The so-called 

 silkworms, like the bees, originated in Asia, and have long 

 been in the care of man. Beginning their experiments in 

 spinning with the wool of animals and the various accessible 

 vegetable fibres, men have ever been seeking materials 

 which could serve them in the weaver's art. At one time 

 or another they have tried an exceeding variety of materials ; 

 in modern days more than a score of insects have been 

 experimented with in the endeavor to obtain fibres which 

 could be turned to use. So far, however, the Bombyx niori 

 — the form which, as its sp^ecific name indicates, feeds upon 

 the leaves of the mulberry tree — is the only one which 

 proves really serviceable. The advantages of this species 

 are found in a peculiar assemblage of qualities, each of 

 which is necessary to make it fit for the ends it attains 

 at the hand of man. 



