MOTIONS OF INSECTS. 461 
hoppers with setaceous antenne (Acrida) have four tarsal joints. Those 
with filiform antennze (Locusta and Acrydium), those with ensiform 
(Truwalis), and the crickets (Gryllus), have only three. In Blatia, the 
variations with respect to the suckers and cushions (for many species are 
furnished with both) are remarkable. The former in some (Blatta gigantea) 
are altogether wanting ; in others (B. Petiveriana) they are mere rudi- 
ments; and in others (B. Mader) they are more conspicuous, and re- 
semble those of the Gryllidez. The foot-cushions also in some are nearly 
obsolete, and occupy the mere extremity of the four first tarsal joints 
(B. orientalis, Americana, Capensis, &c.). In B. Petiveriana there is none 
upon the first joint; but upon the extremity of the four last, not excepting 
the claw-joint, there is a minute orbicular concave one, resembling a 
sucker. In others (B. gigantea, &c.), they extend the length of the four 
first joints, and are very conspicuous. In some (B. Mouffeti K.)?, which 
have no claw-sucker, there appears to be a cavity in the extremity of the 
claw-joint, which may serve the purpose of one. These foot-cushions are 
usually of a pale colour; but in one specimen of a hairy female which I 
have, from Brazil, they are black. The spectre genus (Phasma) exhibits 
no particular varieties in this respect. The tarsal joints of the legs have 
cushions at their apex, which appear to be bifid. They have a large orbi- 
cular sucker between the claws. In Mantis the fore feet have neither of 
the parts in question, and the others have no suckers. They have 
cushions on the four first tarsal joints of the two last pair of legs, which, 
though smaller, are shaped much like those in Phasma. In Acrida the 
feet have no suckers between the claws ; but they are distinguished by 
two oval, soft, concave, and movable processes attached to the base of 
the first joint of the tarsus, which probably act as suckers. In this genus 
there are two foot-cushions on the first joint of the tarsi, and one on each 
of the two following ones. The species of the genus Locusta come next. 
This genus is called Aerydium by listraille after Geoffroy; but, since it 
includes the true docust, it ought to retain the name Locusta given by Linné 
to the tribe to which it belongs.S All these insects have the terminal 
sucker between the claws, three foot-cushions on the first joint of the tarsus, 
and one on the second®; and the same conformation also distinguishes 
the feet of Zruxalis. In the species of Acrydium F. (Tetrix Latr.), the foot- 
of one side have only four joints, while the intermediate one has five. On the other 
side the hind leg is broken off, but the anterior and intermediate tarsi have both 
five joints. In another specimen one posterior tarsus has four and the other five 
joints, 
Pi ane name of this genus, properly spelled, is Zrowallis, from the Greek Ty@arrs, 
ryllus, 
9 This insect, which is remarkable for having the margin of its thorax reflexed, 
was long since well figured in Moutfet’s work (180. jig. mfima). It has not, how- 
ever, been described by any other author I have met with. It is common in Brazil. 
Some specimens are pallid, while others are of a dark brown. It is to be observed 
that the Blattina are resolvable into several genera. 
5 De Geer, iii, 421. t. xxi. f. 13. h. This author has also noticed the cushions in 
this genus and Locusta, and the claw-sucker in the latter, which he thinks are 
analogous to those of the fly. Ibid. 462, t. xxii, f 7, 8 
4 Philos. Trans. 1816. t. xxi. f. 8—13. 
5 See Zool. Journ. for 1825, No. iv. 481. 
6 Philos. Trans, 1816, t. xxi. f. 1—9, 
