MOTIONS OF INSECTS. 303 



run and swim with surprising agility over the bottom 

 of a saucer, in which he had put some cases of these 

 flies ; and at last when he held a piece of stick to it, 

 it got upon it, and having emerged from the water, 

 prepared to cast its envelope. It is remarkable, that 

 the envelope of the intermediate tarsi, like the poste- 

 rior ones of Dytisci, is fringed on one side with hairs, 

 to enable the insects to use them as swimming feet% 

 while those neither of the larva nor imago are so cir- 

 cumstanced. 



I am, &c. 



* De Ocer, ii. 518— 



