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beetle, a kind of bug, and the common blue- 

 bottle. The power with which some insects move 

 their legs is perfectly stupendous the grasshop- 

 er, for instance, being capable of leaping many 

 hundred times its own length, and the flea, of 

 carrying a weight eighty or a hundred times 

 heavier than itself. The strength of a strong 

 man, on the contrary, has been computed by 

 M. Desaguliers rarely to exceed four hundred 

 pounds, or less than three times and a half his 

 own weight ; while that of a weak man is not 

 above one hundred and twenty-five pounds, or 

 less than his own weight. But the most re- 

 markable organs of loco -motion in insects is 

 their wings, which now, for the first time, show 

 themselves in the scale of animals : of these, 

 however, it is sufficient to say, at present, that 

 they are moved by muscles of immense power, 

 and that the velocity with which they are moved, 

 is at least as remarkable as the force. The advan- 

 tage to winged insects of the numerous air-tubes 

 with which their whole bodies are intersected, 

 has been already insisted upon ; and serves beau- 

 tifully to illustrate the harmony of design which 

 characterises their whole economy. 



Most fishes effect loco-motion principally by 

 their fins ; and of these they employ chiefly the pec- 

 toral and ventral pairs, which are strictly analo- 

 gous to the upper and lower extremities of the 

 superior tribes of animals, while the dorsal, cau- 

 dal, arid anal fins are, as it were, a kind of su- 

 pernumerary organs. The two first named pairs 



