312 MOTIONS OF INSECTS. 



a right line. These spines then lay hold of the surface, 

 and by their pressure enable the body to spring for- 

 wards, when, being assisted by its wings, it will make 

 astonishing leaps, sometimes as much as five or six feet, 

 which is more than 250 times its own length ; or as if a 

 man of ordinary stature should be able at once to vault 

 through the air to the distance of a quarter of a mile. 

 Upon glass, where the spines are of no use, the insect 

 cannot leap more than six inches^. — The species of an- 

 other genus of the homopterous Hemiptera {Chermes), 

 that jump very nimbly by pushing out their shanks, are 

 perhaps assisted in this motion by a remarkable horn 

 looking towards the anus, which arms their posterior 

 hip. — Some bugs that leap well, Acanthia saliatoria, &c. 

 seem to have no particular apparatus to assist them, 

 except that their posterior tibiae are very long. — Several 

 of the minute ichneumons also jump with great agility, 

 but by what means I am unable to say. — There is a 

 tribe of spiders, not spinners, that leap even sideways 

 upon their prey. One of these {Salticus sccniciis)^ when 

 about to do this, elevates itself upon its legs, and lifting 

 its head seems to survey the spot before it jumps. 

 When these insects spy a small gnat or fly upon a wall, 

 they creep very gently towards it with short steps, till 

 they come within a convenient distance, when they 

 spring upon it suddenly like a tiger. — Bartram observed 

 one of these spiders that jumped two feet upon a hum- 

 ble-bee. The most amusing account, however, of the 

 motions of these animals is given by the celebrated 

 Evelyn in his Travels. When at Rome, he often ob- 

 served a spider of this kind hunting the flies which 

 * Dc Gccr, iii. 178. 



