ORDER VII. TWO-^^^NGED INSECTS, OR FLIES. 307 



by small ichneumons. These maggots have a skin as strong 

 almost as parchment, two horny hooks near the head, as in 

 the meat-fly, with which they work the cheese and effect 

 their jumping motions. In the performance of this latter 

 feat these disgusting little creatures far excel man or any 

 animal whatever. One of them not longer than a quarter 

 of an inch will jump up into the air six inches — at least 

 twenty-four times its length. How strange that we can 

 look upon the wonderful feats like this, performed by in- 

 significant little insects, without being amazed at the im- 

 mense effort and agility displayed ! It is only because we 

 do not think of them sufficiently deep, and compare their 

 motions Avith our own. The step of a fly is so small in 

 comparison with that of a man, wc do not think to com- 

 pare the number or the speed of their steps to those of man, 

 and yet the latter is the proper light by which to observe 

 them. 



M. Delisle once watched a fly, only as large as a grain of 

 sand, which ran three inches in half a second, and in that 

 space of time made the enormous number of five hundred 

 and forty steps. If a man were to be able to walk as fast, 

 in proportion to his size, supposing his step to measure two 

 feet, he would, in the course of a minute, have run upward 

 of twenty miles — a task far surpassing our express railroad 

 engines, or even the famous " Seven League Boots" record- 

 ed in the nursery fable. So, in jumping or leaping, these 

 insects display astonishing power. Some spiders leap a 

 couple of feet upon their prey. The insect called the 

 "frog-hopper" can leap more than two hundred and fifty 

 times its own length. A flea can leap two hundred times 

 its own length ; so also can the locust. If a man were six 

 feet long, and could leap as high and as far as one of these 

 insects, he might stand near the custom-house in New 

 York, leap up into the air over the top of Trinity Church 

 spire, and alight in Greenwich Street; which would be 



