Mr. Bauer, to correct his former representations of the structure of the feet of the Lacerta Gecko and House Fly, and also to add an account of a similar mechanism in other insects delineated by the same skilful artist.
In the Blue-bottle Fly the suckers are two on each foot, immediately under the root of each claw. Their form is funnel-shaped, with a narrow neck; when not in use they are contracted, and approaching each other lie together in the space between the claws; but when prepared for action they are expanded, and they separate laterally from each other.
In the Horse Fly (the Tabanus of Fabricius,) the suckers differ from the former only in number, as there are three on each foot.
In the yellow Saw Fly (the Cimbex lutea of Fabricius,) suckers are found at each of the four joints of the toes, one at every joint.
In the Dytiscus marginalis, or Great Water Beetle, although for the common purpose of locomotion there is no such apparatus observable at the parts of the feet used in walking, the male is nevertheless abundantly furnished with suckers in the three first joints of the first and second pair of feet; and the purpose to which they are applied is that of embracing the female, who does not want, and is not provided with a similar mechanism. In the male those joints that are furnished with suckers, are of uncommon breadth, having the whole under surface covered with small suckers, to each of which is a small tubular neck.
In addition to the foregoing observations on the suckers by which insects attach themselves to different objects, the author also takes occasion to notice another peculiarity in the feet of some insects, as security against the injury they might sustain in alighting suddenly with considerable velocity.
In some species of Grylli and Locustæ the feet have on their under side globular cushions filled with a fibrous substance, and possessed of considerable elasticity.
In the Locusta varia there are three pair of cushions, of different sizes, at the three first joints of each leg.
But in fleas, which the author examined under an expectation of finding a similar structure, nothing of this sort is to be found; from which it would appear that such a provision is not wanted for resisting the momentum of so light a body, notwithstanding the great distance to which it leaps.
