112 INSECTS. 



Neither is the velocity of the movements of insects 

 inferior to their prodigious muscular power. It has 

 been calculated that in its ordinary flight the common 

 house-fly makes with its wings about six hundred 

 strokes in a second of time, which will carry it a 

 distance of five feet, but if alarmed its velocity can 

 be increased six or seven times, or to thirty or thirty- 

 five feet in a second. In this space of time the 

 swiftest racehorse that ever trod the turf could 

 clear only ninety feet, which is at the rate of more 

 than a mile in a minute. Compare the infinite 

 difference in the size of the two animals (ten millions 

 of the fly would hardly counterpoise one racer), and 

 how wonderful will the velocity of the little insect 

 appear. Did the fly equal the racehorse in size, and 

 retain its present powers in the ratio of its magnitude, 

 it would traverse the globe with the rapidity of 

 lightning. 



Let the reader, therefore, imagine that great law 

 of Nature which restricts the dimensions of an insect 

 within certain bounds, dispensed with even in a single 

 species. Suppose the wasp or the stag-beetle dilated 

 to the bulk of a tiger or of an elephant, cased in 

 impenetrable armour furnished with jaws that would 

 crush the solid trunk of an oak winged and capable 

 of flight so rapid as to render escape hopeless, what 

 could resist such destroyers, or how could the world 

 support their ravages ? 



Insects may, therefore, be regarded in the light of 

 engines, so perfectly adapted to the work intrusted to 

 them, that to increase or diminish their size would 

 be to unfit them for the duties for which they are 

 specially constructed, and as a necessary consequence, 

 no insect in its winged condition can be permitted to 

 grow ; its growth must be effected under other cir- 

 cumstances, and generally under a form quite dif- 

 ferent from that which it presents in its perfect state 

 hence arises the necessity for The Metamorphosis 

 of Insects. 



Most insects in the course of their lives are sub- 



