OF MUSCULAR MOTION. 463 



facility ! Who has not observed an ant-hill, and admired the industry 

 with which these little creatures labour ! Whom has the fact escaped 

 that two or three pismires, or, according to the size of their prey, live 

 or six of them, convey away a large caterpillar, which has by accident 

 come within the limits of their fortifications, and bear it, notwith- 

 standing its violent resistance, to their purposed spot ! In such 

 undertakings they frequently work in opposition to each other, and, 

 under such circumstances, the colossus remains for a time immoveable, 

 retained by equal powers acting in opposition to each other. Lastly, 

 the burying-beetle, how quickly does it not bury its corpse ! From 

 four to six of them are sufficient to bury a moth several inches deep in 

 the course of a quarter of an hour, and even a single beetle would 

 execute this certainly monstrous labour in the course of an hour. Let 

 us only reflect upon the capability of even a dozen men burying a whale 

 in one hour ; and yet the proportions with respect to size are more 

 favourable to the execution of the project in this last case than in the 

 former. 



But the force and duration of muscular motion exhibits itself most 

 conspicuously during flight. We admire the continuous flight of the 

 migratory bird and the rapidity of the swallow, and yet the most 

 common insects exhibit the same phenomena. The well-known dung- 

 beetle flies in warm summer evenings with a rapidity which yields in 

 nothing to the swallow, although it is not one-tenth part its size. The 

 (Estri, Tabani, and flies which pursue cattle and horses with a voracious 

 thirst for blood, excite by the humming noise of their flight the poor 

 objects of their rapacity to escape by resorting to their quickness, but 

 they do not thereby secure themselves from their persecutors, who, 

 quicker than them, at last discover a suitable place of their body for 

 the exercise of their parasitic occupation. We may frequently convince 

 ourselves of their rapidity when riding upon a horse about to be attacked 

 by an (Estrus, upon spurring it to its full speed, for it constantly 

 remains in the vicinity of the animal, at about two or three inches 

 distance from its body, and even at last, when convinced of the im- 

 possibility of executing its purpose, it flies away still faster than the 

 rider, preceding him with incredible rapidity upon his own path. The 

 most remarkable instance of this kind is possibly that related by an 

 English traveller *, who was travelling with a steam- carriage that was 







* In the Philosophical Magazine. 



