330 MOTIONS OF INSECTS. 
the Fabrician genus Gryllus come next. This genus 
is now called <Acrydium by Latreille after Geoffroy ; 
but, since it includes the true Jocust, it ought to have 
retained the name Locusta given by Linné to the tribe 
to which it belongs. All these insects have the terminal 
sucker between the claws, three cushions on the first 
joint of the tarsus, and one on the second*; and the 
same conformation also distinguishes the feet of Truxalis, 
F. In the species of Acrydium, F. (Tetrix, Latr.), the 
cushions, I believe—for in the dead insect they are the 
reverse of conspicuous—are arranged nearly as in the 
two preceding genera, but these insects are without the 
claw-sucker. And lastly, -Acheta, F., has neither 
suckers nor cushions. From this statement it seems to 
follow—since Blatta, Phasma, and Mantis, that do not 
leap, are provided with cushions; and Acheta, F., a 
heavy tribe of insects that does, are without them—that 
their object cannot be exclusively to break the fall of the 
insects that have them. And for the same reason we 
may conclude, that they must have some further use 
than augmenting their elasticity when they jump. When 
we consider that Blatte—many of which have no suckers, 
or very small ones——are climbing insects (I have seen 
B. germanica run up and down the walls of an apart- 
ment with great agility), and that the long and gigantic 
apterous spectres &c. (Phasma) require considerable 
means to enable them to climb the trees in which they 
feed, and to maintain their station upon them, we may 
conclude that these cushions, by acting in some de- 
gree as suckers, may promote these ends. 
* Philos. Trans. 1816. t. xxi. f. 1-9. 
