STRUCTURE OP INSECTS. 69 



by a covering of small scales, which appear to be merely a 

 loose powder, but are in fact fixed by small pedicles or stalks 

 to the membrane itself. They give to those insects their 

 beauty and variety of color. The insects with one pair of 

 wings have underneath them two cylindrical projections ter- 

 minating in a knob, which seem as if they were the rudiments 

 of a second pair. These have been called balancers or poisers, 

 from being supposed to aid them in preserving an equilibrium 

 during their flight. Between them and the wings themselves 

 are found small membranous scales, one* upon each side, 

 against which the balancer strikes with great rapidity whilst 

 the insect is in motion, and causes that buzzing which is then 

 observed. In the various kinds of beetle and other similar 

 insects, the upper pair of wings is of a coriaceous or horny 

 texture, and serves merely the purpose of a case under which 

 the other pair is folded up and protected. In others, as in 

 the grasshopper, the locust, &c., the upper pair is less hard, 

 and has rather the consistence and texture of vellum. 



The abdomen forms the hinder part of the bodies of insects ; 

 it contains the organs of digestion, and is the part from which 

 the eggs of the insect are produced. It is divided into a 

 number of rings or segments. In some, it is furnished with a 

 kind of perforator or auger, with which various substances are 

 bored in order to admit their eggs. In many it is terminated 

 by a sting, as in the wasp and bee, and in others by a forceps, 

 a bristle, or a kind of claw. They display much instinctive 

 intelligence in the deposition of their eggs, placing them in 

 situations best adapted to the nourishment and preservation 

 of their young when hatched, and in some cases even provi- 

 ding food for their immediate wants when they first come 

 into life. 



The greater part of insects, as has just been remarked, 

 after leaving the egg, undergo certain changes of structure 

 and form, before arriving at their perfect state. These changes 

 are called their metamorphoses. They dinW in number in 

 different kinds of insects. 



To take the Butterfly tribe for an example. From the egg 

 of this insect is hatched an animal differing entirely from its 

 parent. Its body is long and cylindrical, and divided into a 

 great many rings. It is provided with a large number of very 

 short legs, with jaws, and with several small eyes. It is famil- 

 iarly known to us by the name of caterpillar. It lives in this 

 state a considerable time, subsisting upon such food as is 

 adapted to its nature. At length it casts off its skin, and 



