MOTIONS OF INSECTS. 



237 



last pairs of perfect legs. 1 To see hundreds of these little 

 animals pendent at the same time from the boughs of a tree, 

 suspended at different heights, some working their way 

 downwards and some upwards, affords a very amusing spec- 

 tacle. Sometimes, when the wind is high, they are blown to 

 the distance of several yards from the tree, and yet maintain 

 their threads unbroken. I witnessed an instance of this last 

 summer, when numbers were driven far from the most ex- 

 tended 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 inhabit that element. 

 Amongst the beetles, the genera Dytiscus, Hydrophilus, 

 Gyrinus, Limnius, Parnus, Heterocerus, Elophorus, Hydrcena, 

 &c. amongst the bug tribes, Gerris, Velia, Hydrometra, 

 Notonecta, Sigara, Nepa, Ranatra, Naucoris ; a few Lepi- 

 doptera ; the majority of Trichoptera ; Libellula, Aeshna, 

 Agrion, Sialis, Ephemera, &c. amongst the Neuroptera ; Culex 

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

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

 Oniscidce, &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 mid- 

 water, either by the same motion of the legs as they use in 

 walking, or by strokes, as in swimming ; 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 surface 

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

 water-motion, since many will come under consideration 

 hereafter. 



There are two descriptions of larvae of Hydropliilidce, one 



1 Reaum. ii. 375. 



