668 EXTERNAL ANATOMY OF INSECTS. 
at the apex of these thighs*; and another family, as 
E. pauperata, have only one on the posterior side. The 
thighs of no insect are more remarkable for their elegant 
shape,—tapering gradually from the base to the apex, 
where they swell again into a kind of knee,—than the 
posterior ones of the locusts; each side of these thighs 
is strengthened with three longitudinal nearly parallel 
ridges, and the upper and under sides are adorned by 
a double series, in some coalescing as they approach 
the tibia, of oblique quadrangular elevations resembling 
scales °. 
I shall next say a few words upon the spines and other 
processes which arm the thigh. ‘Those moveable ones of 
Mantis which help to form a fearful instrument of de- 
struction, have just been mentioned, and similar ones, 
but less conspicuous, arm the intermediate thighs of S7- 
cus flavipes: other appendages of this kind are for a less 
destructive purpose—to keep the tibia when folded in 
its place. This seems to be the use of the serratures 
and spine that arm the thigh of Bruchus Bactris, or the 
Hymenopterous genera Leucospis, Chalcis, &c.; in Onitis 
Aygulus a short filiform horn arms the humerus, and a 
longer crooked one that of many species of Scaurus4. In 
many Stenocort the thighs terminate in two spines, and 
in Gonyleptes the posterior ones are armed internally 
with very strong ones; with which, as the legs converge 
at their knee*, they may probably detain their prey. 
The knee-pan (Gonytheca) of the thigh, or the cavity at 
a Stoll Spectres ubi supr. > Ibid. t. x. f. 40. 
© Prate XIV. Fic. 5. This appearance of scales on the thighs is 
principally confined to this tribe. 4 Prate XXVIL. Fic. 23. 
© Linn. Trans. xii. t. xxi. f. 16. 
