PECULIAR MOTIONS OP INSECTS. 385 



to its mode of life, it being long and of small dia- 

 meter, to enable it to thread its way through narrow 

 holes, while its covering is highly polished to facili- 

 tate its passage, and so hard as to prevent it being 

 lacerated by any splinter of wood which it might 

 chance to encounter, while it is at the same time so 

 flexible, that it can coil itself up into a circle of very 

 small diameter. The hardness and the flexibility, 

 though apparently incompatible, are produced by a 

 similar contrivance to that of the spine in man — the 

 whole body of the julus being composed of small 

 hard rings united by flexible joints.* 



Instances have occurred in which a sheep or a 

 cow has come into the world with legs upon its back : 

 this, of course, is a monstrosity out of the usual course 

 of nature; but in a very singular insect, the bat- 

 louse {JSPijcteribia Hermanni, Leach), the legs 

 appear to have their usual place on the back. ' It 

 transports itself,' says Colonel Montagu, ^ with 

 such celerity, from one part of the animal it inhabits 

 t6 the opposite and most distant, although obstructed 

 by the extreme thickness of the fur, that it is not 

 readily taken.' — ' When two or three were put into 

 a small phial, their agility appeared inconceivably 

 great ; for, as their feet are incapable of fixing upon 

 so smooth a body, their whole exertion was employed 

 in laying hold of each other; and in this most curious 

 struggle, they appeared actually flying in circles: 

 and when the bottle was reclined, they would fre- 

 quently pass from one end to the other with astonish- 

 ing velocity, accompanied by the same gyrations ; if 

 by accident they escaped each other, they very soon 

 became motionless ; and as quickly were the whole 

 put in motion again by the least touch of the bottle 

 or the movement of an individual. 't 



Many of the beetles run with great velocity, and 



* J. R. t Linn. Trans, vol. xi, p. 13. 



VOL. VI. 33 



