THE STRUCTURE AND LIFE OF INSECTS 249 



insects are found in this country. What the exact size of 

 the smallest insect may be I cannot tell ; I have seen a 

 full-grown parasitic fly escape from an insect-egg, which 

 was not distinctly visible to the naked eye. 



The small size of insects throws some light upon their 

 extreme ingenuity. Being unable to defend themselves 

 or to attack other animals by main force, they have com- 

 monly to use artifice instead. The disguises of insects 

 are innumerable ; they escape notice by their resemblance 

 to leaves, sticks, bird-droppings, and an infinity of other 

 objects ; they creep into crevices, or spin together particles 

 of sand, wood, leaves and shells ; many of them, when 

 alarmed, sham dead. Though few insects are formidable 

 to other animals by reason of their biting power, many 

 can sting, injecting a -poison into the minute wound which 

 they make, a poison which is far more dreaded than the 

 wound itself. 



.THE STRENGTH OF INSECTS. 



There is a wide- spread but quite mistaken impression 

 that, if fair allowance is made for their small size, insects 

 will be found to be the very strongest of animals. Kirby 

 and Spence tell us that a cockchafer, allowing for difference 

 of size, is six times as strong as a horse, and they confirm 

 the estimate of Linnaeus that if the elephant were as strong 

 in proportion as the stag-beetle, he would be able to level 

 mountains. Such statements as these are based on the 

 supposition that if one animal is ten times as long as 

 another, it should be able to draw or lift ten times as 

 much, but this is altogether fallacious. If the larger 

 animal were identical in shape and build with the smaller 

 one, it should be a hundred times as strong, while it would 

 weigh a thousand times as much. The proportion 01 

 muscular strength to weight falls therefore as the size 

 increases, and before long the animal would, as a mere 

 consequence of increased size, become incapable of moving 

 its body at all. It is only because the horse is expressly 



