MOTIONS OF INSECTS. 309 



see the undulating line of motion successively begin- 

 ning at the head and passing off at the tail. — The mo- 

 tion of centipedes (Scolopendra), as well as that of this 

 insect and itscongeners, is retrogressive as well as pro- 

 gressive. Put your finger to the common one (S. mor- 

 sitaus, L.), and it will immediately retrograde, and with 

 the same facility as if it was going forwards. This dif- 

 ference, however, is then observable — it uses its four 

 hind legs, which, when it moves in the usual way, are 

 dragged after it. — Almost all the other apterous insects, 

 as well as many of those in the other orders, can move 

 in all directions ; backwards, and towards both sides, 

 as well as forwards. Bonnet mentions a spider (not a 

 spinner) that always walked backwards when it at- 

 tacked a large insect of its own tribe ; but when it had 

 succeeded in driving it from a captive fly, which how- 

 ever it did not eat, it walked forwards in the ordinary 

 way''. 



Insects vary much in their walking paces : some 

 crawling along ; others walking slowly ; and others 

 moving with a very quick step. The field-cricket 

 iAchcia campcstris, F.)'creeps very slowly — the bloody- 

 nose beetle {Chri/somela ienchricosa) and the oil-beetle 

 Meloe Proscarabceus) march very leisurely; while 

 flies, ichneumons, wasps, &c., and many beetles, walk 

 as fast as they can. One insect, a kind of snake-fly 

 (Raphidia Manlispa, F.), is said to walk upon its knees. 

 The crane-flies (Tipula oleracea, L.), and shepherd 

 spiders {Phalangium, L.) have legs so disproportion- 

 ately long, that they seem to walk upon stilts; but 

 when we consider that they have to walk over and 



