EXTERNAL ANATOMY OF INSECTS. 673 
words upon the flexure of this joint, which in some cases 
merits notice. I have before mentioned its bend at the 
knee* or base: the apex also is sometimes incurved—in 
the anterior one of the male of Acrocinus longimanus so 
as almost to form a hook”: in Lyg@us Pharaonis the 
posterior pair are flexuose®; in Bruchus Bactris, Leu- 
cospts, and seyeral species of Chalcis, these tibie@ curve 
so as to adapt themselves to the bend of the thigh when 
folded. The notch on the inside of the anterior pair, in 
a large majority of Carabus L., armed above by a spur 4, 
astructure which probably assists them in seizing and de- 
taining their prey, may also here be introduced: in the 
generality it is a little removed from the apex of the joint 
in question; but in Pamborus it is very near to it, and 
in Cychrus, Carabus, &c., it becomes obsolete. I may 
mention herealsoa singular character which distinguishes 
the cubit of both sexes of Gryllus campestris, domesti- 
cus, &c. At the base there is an aperture which passes 
through the joint—anteriorly it is oval, and posteriorly 
elliptical and much larger, and on both sides is closed 
by a tense membrane. 
The most striking peculiarities as to the clothing of 
this joint have been chiefly noticed under the sexual cha- 
racters of insects*, but some appear not to be of that 
description. In Spheridium while the thighs and tarsi 
are naked, the posterior ¢2b¢@ are remarkably beset with 
stiff bristles; in Empis pennipes they are thickly fringed 
on both sides; in Scarabeus only externally, and in 
* See above, p. 67 0. 
-> Oliv. Ins. n. 66. ¢. iii. f. 12. Compare Scarabeus longimanus, 
Ibid. n. 3. t. iv. f. 27. * Stoll Punaises, t. ii. f. 20. 
4 Prate XXVILI. Fic. 31. * See above, p. 305—. 
VOL. If. 2X 
