452 MOTIONS OF INSECTS. 
which the tibie, when the legs are unbent, are impelled with greater force, 
In the Orthoptera order, all the grasshoppers, including the genera Gry/. 
lotalpa, Gryllus, Tridactylus, Locusta, Acrida, Plerophylla, Pneumora, Trix. 
alis, Acrydium, Tetrix, &c., 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 Coleoptera that are furnished 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 
Jeap two hundred times its own length.'— 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.’ 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 (Gidemera 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 Anobium 
and Ptilinus, found by our friend the Rey. R. Sheppard, and which I have 
named after him Choragus Sheppardi, is similarly cireumstanced. In the 
various tribes of frog-hoppers (Cercopide, &c.), 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, ora 
series of strong spines, by pressing which against the plane of position they 
are supposed to be aided in effecting this motion. On this occasion they 
bend their legs like the grasshoppers, and then unbending kick them out 
with violence.t Many of them, amongst the rest Anthrophora spumaria, 
have the extremity of the above tibia 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 
erpendicular 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 surface, 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 0 
ordinary stature should be able at once to vault through the air to the 
«listance of a quarter of a mile. Upon glass, where the spines are of no 
1 Swamm., Bibl. Nat, Ed. Hill, i, 128. b. 
2 Aristoph. Wubes, Act. i. Se. 2. 
§ Trost, Beitrige, 40. 4 De Geer, iii. 161. 
