Fis. 56. — Asfaoun fluviafUis. — The structure of the cuticle. j1, trans- 

 verse section of a joint of the forceps ( x i) ; n, setse ; B, a por- 

 tion of the 'same ( x 30) ; C, a portion of B more highly magnified, 

 a, epiostracum ; i, ectostracum ; c, endostraoum ; d, canal of seta ; 

 e, canals filled with air ; s, seta. J), section of an interstemal 

 membrane of the abdomen, the portion to the right in the natural 

 condition, the remainder pulled apart with needles ( x 20) ; H, 

 small portion of the !<ame, highly magnified ; a, intermediate sub- 

 stance i *, laminae, -f, a seta, highly magnified ; a and b, joints. 



