252 



MOTIONS OF INSECTS. 



bring the shank into close contact with the thigh, which 

 has often a longitudinal furrow armed with a row of spines 

 on each side to receive it. The leg being thus bent, they 

 suddenly unbend it with a jerk, when pushing against the 

 plane of position, they spring into the air often to a con- 

 siderable height and distance. A locust, which, however, is 

 aided by its wings, it is said will leap two hundred times its 

 own length. 1 — Aristophanes, in order to make the great and 

 good Athenian philosopher, Socrates, appear ridiculous, re- 

 presents him as having measured the leap of a flea. 2 In our 

 better times scientific men have done this without being 

 laughed at for it, and have ascertained that, comparatively, 

 it equalled that of the locust, being also two hundred times 

 its length. Being effected by muscular force, without the 

 aid of wings, this is an astonishing leap. There are several 

 insects, however, which, although they are furnished with 

 incrassated posterior thighs, do not jump. Of this descrip- 

 tion are some beetles belonging to the genus Necydalis ( (E-de- 

 mera Oliv.), in which this seems a peculiarity of the male : 

 and amongst the Hymenoptera, not to mention others, several 

 species of Chalcis, and all that are known of that singular 

 genus Leucospis. 



Many insects, that jump by means of their posterior legs, 

 have not these thighs. This is said to be the case with Sca- 

 phidium, a little tribe of beetles 3 : and one of the same order, 

 that seems to come between Anobium and Ptilinus, found by 

 our friend the Rev. R. Sheppard, and which I have named 

 after him Choragus Sheppardi, is similarly circumstanced. 

 In the various tribes of frog-hoppers (Cercopidce, &c.) the pos- 

 terior tibia3 appear to be principally concerned in their leaping. 

 These are often very long, and furnished, on their exterior 

 margin, with a fringe of stiff hairs, or a series of strong spines, 

 by pressing which against the plane of position they are sup- 

 posed to be aided in effecting this motion. On this occasion 

 they bend their legs like the grasshoppers, and then unbend- 

 ing kick them out with violence. 4 Many of them, amongst 



' Swamra. Bibl. Nat. Ed. Hill, i. 123. b. 



2 Aristoph. Nubes, Act. i. Sc. 2. 



3 Trost, Beitrage, 40. 4 De Geer, iii. 161. 



