MOTIONS OF INSECTS. 331 



Amongst the Hemiptera^ Chermes and many of the 

 CicadiadcB^ are furnished with the claw-suckers ; but 

 the noisy Tettigonice^ as well as the tribes of Cimicidce^ at 

 least as far as my examination of them has gone, have 

 them not. De Geer has observed, speaking of a small 

 fly of this order {Thrips Physapus^ L.)? that the ex- 

 tremity of its feet is furnished with a transparent mem- 

 branaceous flexible process, like a bladder. He further 

 says that, when the animal fixes and presses this ve- 

 sicle on the surface on which it walks, its diameter is 

 increased, and it sometimes appears concave, the con- 

 cavity being in proportion to the pressure ; which made 

 him suspect that it acted like a cupping-glass, and so 

 produced the adhesion''. This circumstance affords 

 another proof that the cushions in the Orthoptera may- 

 act the same part; they appear to be vesicular; and in 

 numbers of specimens, after death, 1 have observed 

 that they become concave, particularly in Locusta vi- 

 ridissima. 



In Cimbex, and others amongst the saw-fly tribes 

 (Tenthredinidce), the claw-sucker is distinguished by 

 this remarkable peculiarity, that its upper surface is 

 concave '^, so that before it is used it must be bent in- 

 wards. Besides these, at the extremity of each tarsal 

 joint these animals are furnished with a spoon-shaped 

 sucker, which seems analogous to the cushions in the 

 Gryllidoi : and, what is more remarkable, the two spurs 

 (calcaria) at the apex of the shanks have likewise each 

 a minute one"*. — Various other insects of this order 

 have the claw-suckers. Amongst others the common 



" Do Geer, iii, 132. 173. " Ibid. 7. 



" Philos. Trans. 1816. t. xix. /. 3,4. " Ibid. t. xix. /. 1-9. 



