270 MOTIONS OF INSECTS. 



lion ; they either walk, or jump, or swim. I use 

 walking in an improper sense, for want of a better term 

 equally comprehensive : for some may be said to move 

 by gliding; and others (I mean those that, fixing the 

 head to any point, bring the tail up to it, and so pro- 

 ceed) by stepping. 



The motion of serpents was ascribed by some of the 

 ancients (who were unable to conceive that it could be 

 effected naturally, unless by the aid of legs, wings, or 

 fins,) to a preternatural cause. It was supposed to re- 

 semble the " incessus deorum" and procured to these 

 animals, amongst other causes, one of the highest and 

 most honourable ranks in the emblematical class of their 

 false divinities*. Had they known Sir Joseph Banks's 

 late discovery, that some serpents push themselves 

 along by the points of their ribs, which Sir E. Home 

 has found to be curiously constructed for this purpose, 

 their wonder would have been diminished, and their 

 serpent^gods undeified. But though serpents can no 

 longer make good their claim to motion more deorum, 

 some insects may take their places ; for there are num- 

 bers of larvae, that having neither legs, nor ribs, nor 

 any other points by which they can push themselves 

 forward on a plane, glide along by the alternate con- 

 traction and extension of the segments of their body. 

 Had the ancient Egyptians been aware of this, their 

 catalogue of insect divinities would have been wofully 

 crowded. In this annular motion, the animal alternately 

 supports each segment of the body upon the plane of 

 position, which it is enabled to do by the little bundles 



* Encycl. Brit., art. Physiology, 709. 



