INSECTS. 



511 



roof, are laid flat upon the back. Some of them possess 

 ocelli, whilst others are destitute of those organs. The 



Tig. 265. 

 J, Leg of Gyrinus, Whirligig, with paddle expanded. 2, With paddle closed up. 



wings are very long, and folded up in such a manner 

 as to project beyond the wing-cases in the form of a 

 pair of tapering tails; the abdomen is also furnished, 

 in both sexes, with a pair of pilose, bristle- shaped, 

 caudal appendages ; in the female these form a long slender 

 ovipositor, the two filaments being placed side by side, 

 and somewhat thickened at the tip. The tarsi are three- 

 jointed. The horny covering and muscular apparatus 

 under the wing-cases 

 of the Cricket are very 

 curious and will repay 

 for a careful examina- 

 tion. The Cricket has F '^ '~ The Cricket - 

 two wings, covered by elytra or wing-cases of a dry mem 

 branous consistency, near the base of which is a horny 

 ridge having transverse furrows, exactly resembling a rasp 

 or file; this it rubs against its body with a very brisk 



