INSECTS: WINGS AND THEIR APPENDAGES 87 



that in its ordinary flight the House-fly makes about 600 

 strokes with its wings every second, and that it is carried 

 through the air a distance of five feet during that brief 

 period. But, if alarmed, the velocity can be increased 

 six or seven fold, as every one must have observed, so 

 as to carry the insect thirty or five- and- thirty feet in the 

 second. In the same space of time, observes Mr. Kirby, 

 a race- horse could clear only ninety feet, which is at the 

 rate of more than a mile a minute. Our little fly, in her 

 swiftest flight, will in the same space of time go more than 

 the third of a mile. Now compare the infinite difference 

 of the size of the two animals (ten millions of the fly would 

 hardly counterpoise one racer), and how wonderful will 

 the velocity of this minute creature appear ! Did the fly 

 equal the race-horse in size, and retain its present powers 

 in the ratio of its magnitude, it would traverse the globe 

 with the rapidity of lightning. 1 



Bees, again, are accomplished masters of aerial motion. 

 The Humble-bees, notwithstanding their heavy bodies, are 

 the most powerful fliers of this class. The same excellent 

 entomologist tells us that they "traverse the air in seg- 

 ments of a circle, the arc of which is alternately to right 

 and left. The rapidity of their flight is so great that, 

 could it be calculated, it would be found, the size of the 

 creature considered, far to exceed that of any bird, as has 

 been proved by the observations of a traveller in a rail- 

 way carriage proceeding at the rate of twenty miles an 

 hour, which was accompanied, though the wind was against 

 them, for a considerable distance by a Humble-bee (Bom- 

 bus subinterruptus), not merely with the same rapidity, 

 but even greater, as it not infrequently flew to and fro 



1 "Intr. to Entom.," Lett. xxii. 



