52 



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 ac- 

 count 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, imme- 

 diately under the root of each claw. Their form is funnel-shaped, 

 with a narrow neck ; when not in use they are contracted, and ap- 

 proaching 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 ob- 

 servable at the parts of the feet used in walking, the male is never- 

 theless 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 Locustse 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 resist- 

 ing the momentum of so light a body, notwithstanding the great di- 

 stance to which it leaps. 



A new Demonstration of the Binomial Theorem. By Thomas Knight, 

 Esq. Communicated by W. H. Wollaston, M.D. Sec R.S. Read 

 July 4, 1816. [Phil. Trans. 1816, p. 331.] 



On the Fluents of irrational Functions. By Edward Ffrench Brom- 

 head, Esq. M.A. Communicated by J. F. W. Herschel, Esq. F.R.S. 

 Read June 4, 1816. [Phil. Trans. 1816, p. 335.] 



