INSECTS HAVE NOT BONES. 339 



to cut open the dead body of a fly, we should look 

 in vain for anything like the back-bone, or the 

 bones of the legs. But it must not, therefore, 

 be thought that insects have no skeleton at all. 

 Their skeleton is the thick, hard, horny substance 

 which forms their external covering. In the wasp, 

 for instance, it will be easily perceived, on pressing 

 the head or the trunk of the insect between the 

 fingers, that there is a very firm, solid coating, 

 protecting the tender and delicate organs within. 

 It is a very singular fact that the wisdom of the 

 Creator has so ordered this outside coating, that 

 where it is most necessary to be strong, as for 

 example, when an insect has to burrow through 

 the ground, or is in danger of being often crushed, 

 there its thickness is greatest ; and again where, 

 as in the case of those insects which live chiefly in 

 the air, this thickening is less necessary, because 

 there is less risk of injury to its body, there the 

 external covering is thinner and softer. So extra- 

 ordinarily is one insect strengthened in its external 

 coats, that it is scarcely possible to crush it by the 

 hardest squeezing between the thumb and fingers. 

 It has, on this account, been compared to a once 

 famous London character, called "Leather-coated 



