MOTIONS OF INSECTS. 487 



the genera Gryllotalpa, GryUiis, Tridacti/lus, Locusta, Acrida, Ptero- 

 phylla, Pneumora, Truxalis, Acrydiurn, Tetrix, Sic, are distinguished by 

 incrassated posterior thighs ; which, however, are much longer, more 

 tapering and shapely (they are indeed somewhat clumsy in the two first 

 genera, the crickets), than those of most of the Colcopiera that are fur- 

 nished with them. When disposed to leap, these insects bend their hind 

 leg so as to 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 considerable height and distance. A locust, which, however, is 

 aided by its wings, it is said will leap two hundred times its own length.^ 

 — Aristophanes, in order to make the great and good Athenian philoso- 

 pher, Socrates, appear ridiculous, represents him as having measured the 

 leap of a flea.^ 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 description are some beetles belonging to the genus Necydalis ((E-rfe- 

 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 Scaphidium, a little tribe 

 of beetles^ : and one of the same order, that seems to come between Aiio- 

 bium and Piilinus, 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, he.) the posterior tibiae 

 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 posi- 

 tion they are supposed to be aided in effecting this motion. On this occa- 

 sion they bend their legs like the grasshoppers, and then unbending kick 

 them out with violence.'* Many of them, amongst the rest Anthrophora 

 spumaria, have the extremity of the above tibiae armed with a coronet of 

 spines ; these are of great use in pushing them off when the legs are 

 unbended. This insect, when about to leap, places its posterior thighs in 

 a direction perpendicular to the plane of position, keeping them close to 

 the body ; it next with great violence pushes them out backwards, so as 

 to stretch the leg in a right line. These spines then lay hold of the sur- 

 face, and by their pressure enable the body to spring forwards, when, 

 being assisted by its wings, it will make astonishing leaps, sometimes as 

 much as five or six feet, which is more than 250 times its own length ; or 

 as if a man of ordinary stature should be able at once to vault through 

 the air to the distance of a quarter of a mile. Upon glass, where the 

 spines are of no use, the insect cannot leap more than six inches.^ The 



' Snnjnm. Bibl. Nat. Ed. Hill, i. 123. b. * Arisloph. Nubes, Act. i. Sc. 2. 



3 Trost, Beilrage, 40. * De Geer, iii. 161. * De Geer, iii. 178. 



