26 OUR INSECT FRIENDS AND FOES 



Where " sleeving " is not possible, or is un- 

 desirable, wooden breeding cages should be 

 used. These breeding cages are best constructed 

 with a glass front and top for observation 

 purposes, and with fine perforated zinc let into 

 the sides, so that there is plenty of light and 

 air. It is advisable to have the cages fitted with 

 a removable tray at the bottom, which can hold a 

 layer of mould about an inch deep. This layer 

 of earth is particularly important if the larvae of 

 Moths are being kept under observation, because 

 a very large number will be found to pupate 

 just beneath the surface of the soil. A little 

 moss and a few pieces of bark should also be 

 placed in the cage, to afford suitable accommoda- 

 tion for those larvae which do not pupate in 

 the soil. The food plant should be introduced 

 into these cages in narrow-mouthed jars, filled 

 with water to keep the plants moist and fresh ; 

 while to prevent the larvae creeping or falling 

 into the water, the mouth of the jars should be 

 covered by a metal or wooden perforated cap, 

 having apertures just large enough to take the 

 stems of the food-plant. 



For keeping aquatic insects under observa- 

 tion, it will be necessary to provide a few aquaria. 

 The most inexpensive forms are the small globes 

 sold for keeping one or two gold-fish, but there 

 is one very great objection to these, and that is 

 the great distortion caused by the rounded sides, 

 which quite prevent one being able to obtain a 

 clear, direct view of the creatures they contain. 

 Small square or oblong tanks are much to 

 be preferred, and are now made in quite a 



