MOTIONS OF INSECTS. 291 



nessed an instance of this last summer, when numbers 

 were driven far from the most extended branches, and 

 looked as if they were floating in the air. 



Having related to you what is peculiar in the motions 

 of pedate larvae upon the earth and in the air, I must 

 next say something with respect to their locomotive 

 powers in the water. Numbers of this description in- 

 habit that element. Amongst the beetles, the genera 

 Dytiscus, Hydrophilus, Gyrinus, Limnius, Parnus, He- 

 terocerus, Elophorus, Hydrcena, &c. amongst the bug 

 tribes, Gerris, Velia^ Hydrometra, Notonecta, Sigara, 

 Nepa, Ranatra, Naucoris ; a few Lepidoptera; the ma- 

 jority of Trichoptera; Libelluta, Aeshna^ Agrion, Sialis, 

 Ephemera, &c. amongst the Nenroptera ; Culex and 

 many of the Tipularice, Latr. from the dipterous insects ; 

 and from the Aptera, Atax, some Podurce, and many of 

 the Oniscidte, &c. All these, in their larva state, are 

 aquatic animals. 



The motions of these creatures in this state are 

 various. Some walk on the ground under water ; some 

 move in midwater, either by the same motion of the 

 legs as they use in walking, or by strokes, as in swim- 

 ming; others for this purpose employ certain laminae, 

 which terminate their tails, as oars ; others again swim 

 like fish, with an equable motion ; some move by the 

 force of the water which they spirt from their anus ; 

 others again swim about in cases, or crawl over the 

 submerged bottom; and others walk even on the sur- 

 face of the water. I shall not now enlarge on all these 

 kinds of water-motion, since many will come under con- 

 sideration hereafter. 



There are two descriptions of larvae of Hydrophili, 



