MOTIONS OF INSECTS. 365 



Some insects, that are not naturally aquatic, if they 

 fall into the water will swim very well. 1 once saw a 

 kind of grasshopper (Acrj/dium^ F.), which by the pow- 

 erful strokes of its hind legs pushed itself across a 

 stream with great rapidity. 



Other insects walk, as it were, in the water, moving 

 their legs much in the same way as they would do on 

 the land. Many smaller species of water-beetles, be- 

 longing to the genera Hydrophilus, Elophorus, Ily- 

 drcena, Parnus^ Elmis, &c., thus win their way in the 

 waves. — Thus also the water-scorpion (iVepa) pursues 

 its prey ; and the little water-mites {Hydrachnci) may 

 be seen in every pool thus working their little legs with 

 great rapidity, and moving about in all directions. — 

 Some spiders also will not only traverse the surface of 

 the waters, but, as you have heard with respect to one% 

 descend into their bosom. There are other insects 

 moving in this way that are not divers. Of this kind 

 are the aquatic bugs {Gerris lacustris, JJj/drometra 

 Stagnorum, Velia Rivulorum, &c., Latr.). The first 

 can walk, run, and even leap, which it does upon its 

 prey, as well as swim upon the surface. The second, 

 remarkable for its extreme slenderness, and for its pro- 

 minent hemispherical eyes — which, though they are 

 really in the head, appear to be in the middle of the 

 body — rambles about in chase of other insects, in con- 

 siderable numbers, in most stagnant waters. The 

 Velia is to be met with chiefly in running streams and 

 rivers, coursing very rapidly over their waves. The 

 two last species neither jump nor swim. 



I am next to say a few words upon the motions of 



' Vol. I. 2d Ed. 473. 



