Microscopical Essays. 



and pupa ftate, live in the water ; but when they have a {Turned 

 their perfect form, they are entirely terreftrial, and would be 

 drowned therein. 



The notone&a, the nepa or aquatic fcorpion, Sec never quit 

 the water till they have patted through all their transformations, 

 when they become amphibious, generally quitting it in the 

 evening. 



The water-beetles, of which there are many fpecies, remain in 

 •the water all day, but towards evening come upon the ground 

 and fly about, but plunge themfelves again in the water at the 

 approach of the rifmg fun. The larvae of thefe infects are entirely 

 aquatic ; but when the time of their pupa ftate arrives, they take 

 to the earth, where they make a fpherical cafe : fo that thefe in- 

 fers are aquatic as larva, terreftrial as pupa, and amphibious in 

 the imago ftate. 



We find an inftanee of an infect that lives at the fame time in 

 the water and the air, in the fmgular larva defcribed by M. de 

 Reaumur, Memoires de 1'Acad. in 17 14, p. 200. It has the head 

 and tail in the water, while the reft of the body is continually 

 kept above the furface. In order to fupport itfelf in this fmgular 

 pofition, it bends the -body, bringing the head near the tail, 

 railing the reft above the water, and fup porting itfelf againft 

 feme fixed object, as a plant, or againft the borders of the pond ; 

 or, if it is placed in a glafs veffel, againft the fides of the veffel; 

 and if the glafs be inclined gently, fo that the water may nearly 

 -cover the larva, it immediately changes it's pofition, in order that 

 part of the body may be kept dry. 



At 



