PRESERVATION OF INSECTS. 369 



Water-net. 



channel. In consequence of aquatic insects, for the 

 most part, preying upon one another, they are usually 

 very nimble in their movements, so that it requires 

 considerable dexterity and quickness to entrap them. 

 For the same reason a number of phials, containing 

 water, will be as requisite to carry them as pill-boxes 

 to carry the land-insects. But when they are kept in 

 wine or ale-glasses, and supplied with food, they fur- 

 nish excellent materials for interesting observation. 

 It is easy, indeed, in this way to have several suc- 

 cessive generations, and when gnats' eggs are pro- 

 cured the whole history of these curious insects may 

 be traced with little difficulty. When the pupae are 

 observed to be about to be transformed into winged 

 insects, a gauze covering may be employed to pre- 

 vent their escape. 



Analogous to the water-net in size and construc- 

 tion is the butterfly -net, which is chiefly used on 

 the continent, though seldom, we believe, in this 

 country. It consists of a hoop, about a foot in 

 diameter, of brass or iron wire, jointed or not, so as 



