PRESERVING WATER ANIMALS 



fasten a tag to the cage, writing name or number with the 

 date, and keep a note-book record of them. Make the cage 



-^ 



1 



Pjc. 33.— Cage for rearing water insects: i, cylinder 

 of wire window-screening with hem; 2, finished cage 

 with ends folded, detail of hem. (After Needham.) 



safe from floods and plunder; visit it every day or two if 

 possible. The winged insect should soon be found at the 

 top of the cage with its cast skin clinging to the cage side 

 below. The cast off skin and the winged insect should be 

 preserved in alcohol as a record of its immature and adult 

 stages. Many quiet- water insects can be kept for a few days^ 

 in screen-covered dishes within doors and their changes from' 

 nymph to adult go on equally well there. 



Aquaria.— Put a layer of sand in a tumbler, plant a branch 

 or two of Elodea in it, fill the glass with water from the pond 

 and then let it settle. Put a couple of pond snails into it— 

 and the aquarium is complete-made simply enough, yet 

 here a snail can live through a sample of its normal daily life 



37 



