330 MOTIONS OP INSECTS. 



the Fabriclan genus Gryllus come next. This genus 

 is now called Acrydium by Latreille after GeofFroy ; 

 but, since it includes the true locust^ it ought to have 

 retained the name Locusta given by Linne to the tribe 

 to which it belongs. All these insects have the ter- 

 minal 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 

 Truxatis, F. In the species o£ Acrj/diufn, F. (TetrLv, 

 JjB.tr.), 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 in- 

 sects are without the claw-sucker. And lastly, Achetd, 

 F., has neither suckers nor cushions. From this state- 

 ment it seems to follow — since Blatto, 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 must conclude, that they must 

 have some further use than augmenting their elasticity 

 when they jump. When we consider that Blattce — 

 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 apartment with great agi- 

 lity), and that the long and gigantic apterous spectres 

 &c. {Pliasma) 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 degree as suckers, 

 may promote these ends. 



• Fhilos. Trans. 1816. t.xxi. /. 1-9, 



