MOTIONS OF INSECTS. 299 



of the wise provision of the beneficent Father of the 

 universe for the welfare of his creatures. The antennae 

 and legs of this tribe of insects, when they are pupae, 

 are not included, as is the case with most that are qui- 

 escent in that state, in the general envelope ; but each in 

 a separate one, so as to allow it free motion. Thus the 

 insect when the time is come for its last change can use 

 them (except the hind-legs, which being partly covered 

 by the wing-cases remain without motion) with ease. It 

 then stretches out its antennae, and steering with its legs 

 makes for the surface. De Geer saw one just escaped 

 from its case 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 

 posterior ones of Dytisci, is fringed on one side with 

 hairs, to enable the insects to use them as swimming 

 feet a , while those neither of the larva nor imago are so 

 circumstanced. 



I am, &c. 

 a DeGeer, ii. o!8 



