( 42 ) 



reprefented thofe two parts which, when joined together as I have 

 before laid, conftitute the fheath, and are covered with many hairs. 

 At L M and L P are the llings or piercers ; and in one of them, 

 L M, may be feen the cavity in which the other of them, L P, is 

 placed, when both are at reft : and when thefe two piercers are 

 inclofed in the Iheath, thefe four organs may be taken for one lingle 

 iiing. 



While I was employed about thefe obfervations, my fervants 

 brought me a Flea, fixed to a fmall needle. Upon placing this before 

 the microfcopc, I faw not much motion in its feet, and the ftings 

 or piercei*s were put forth from their cafe; and the fting, L P, which 

 was inclofed in the cavity of the fting, L M, was moved up and 

 down in a very pretty manner, with great fwiftnefs, and as it were 

 in play. 



Moreover, farther to gratify the curious, I pulled off one of the 

 Flea's hind legs ; in doing which, part of the mufcle belonging to 

 it was fcparatcd from the body, this I fixed to the point of a brals 

 pin, in order the better to place the whole leg before a microfcope 

 of greater magnifying power, and to caufe a drawing to be made 

 of its true fliape. 



F/g. 20, B C D E F G H I K L M N, reprefents this hind leg; A B 

 is the mufcle, feparated from the animal's body at A. The firft joint 

 is flicwn at C D M N, and B C N is the part by which it had been 

 united to the body: in this firft joint might very plainly be fecn 

 four diftinA parts, lying longitudinally, and probably were tendons 

 and blood veftels ; which vellcls, and their more minute ramifica- 

 tions, I could plainly fee. This joint, and all the others feen. 

 through the microfcope, exhibited a tranfparent yellow colour, like 

 that of amber. 



Between the letters D E L M maybe feen the perfect articulation, 

 whereby this firft was united to the fecond joint. 



E F R L, reprefents the fecond joint, in the middle of which not 

 only the nervous or mufcular parts lying lengthways, were plainly 



