MOTIONS OF INSECTS. 33% 
Amongst the Hemiptera, Chermes and many of the Ci- 
cadiade* are furnished with the claw-suckers; but the 
noisy Tettigonia, as well as the tribes of Cimicide, 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 extre- 
mity of its feet is furnished with a transparent membra- 
naceous flexible process, like a bladder. He further 
says that, when the animal fixes and presses this vesicle 
on the surface on which it walks, its diameter is increas- 
ed, and it sometimes appears concave, the concavity 
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, I have observed that they become 
concave, particularly in Locusta viridissima. 
In Cimbex, and others amongst the saw-fly tribes 
(Tenthredinide), the claw-sucker is distinguished by 
this remarkable peculiarity, that its upper surface is con- 
cave‘, so that before it is used it must be bent inwards. 
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 Gryllide: 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 wasp (Vespa vulgaris) is by 
these enabled to walk up and down our glass windows. 
* De Geer, itt. 132. 178. b Ibid. 7. 
© Philos. Trans. 1816. t. xix. f. 3, 4. d Ibid. £. xix. f. 1-9, 
