304? MOTIONS OF INSECTS. 



that have more than six feet move in this way which is 

 not improbable from the difficulty of attending at the 

 same time to the movements of so many members, is not 

 easily ascertained. 



The dog-tick (Ixodffs Ricinus\ if when young and 

 active it moves in the same way that it does when swoln 

 to an enormous size with blood, seems to afford an ex- 

 ception to the mode of walking just described. It first 

 uses, says Ray, its two anterior legs as antennae to feel 

 out its way, and then fixing them, brings the next pair 

 beyond them, which being also fixed, it takes a second 

 step with the anterior, and so drags its bloated carcase 

 along a . Redi observes, that when scorpions walk they 

 use those remarkable comb-like processes at the base of 

 their posterior legs to assist them in their motions, ex- 

 tending them and setting them out from the body, as if 

 they were wings : and his observation is confirmed by 

 Amoreux, who calls them ventral swimmers b . I have 

 often noticed a millepede (Julus terrestris], frequently 

 found under the bark of trees, and where there is not a 

 free circulation of air, the motions of which are worthy 

 of attention. Observed at a little distance, it seems to 

 glide over the surface, like a serpent, without legs ; but 

 a nearer inspection shows how its movement is accom- 

 plished. Alternate portions of its numerous legs are ex- 

 tended beyond the line of the body, so as to form an ob- 

 tuse angle with it, while those in the intervals preserve 

 a vertical direction. So that, as long as it keeps moving, 

 little bunches of the legs are alternately in and out from 

 one end to the other of its long body ; and an amusing 



a Hist. Ins. 10. b Redi Opusc. i. 80. Amoreux, 44 



