310 APPARATUS USED BY ENTOMOLOGISTS. 



of the plants may be put for the caterpillars to feed on. The most 

 convenient size of the cages is about eight inches in breadth, four deep, 

 and one foot in height; they should never contain but one kind of ca- 

 terpillar, as some species devour others ; and indeed, if left without 

 food, will devour those of their own kind also. At the bottom of each 

 case must be a quantity of earth, about two inches deep ; with the 

 earth should be mixed a little sand, and some of the fine mould fre- 

 quently found in the bodies of old trees ; this will prevent in a great 

 measure the earth drying up into hard lumps or clods. The most cer- 

 tain way of breeding insects is to keep the cages in a cool and moist 

 place, as in a cellar or out-house ; for a great nimiber of caterpillars 

 change into the ])upa state several inches beneath the surface of the 

 earth, and if kept too dry, the earth about them will absorb the nutri- 

 tive moisttire from the animal, thereby not only weakening it, but 

 hardening the shell in which it is inclosed, so that its strength will be 

 insufficient to burst the case when it should come forth, and in which 

 it must die, as many have done, occasioned entirely by this mis- 

 management of them. 



Some years produce a greater quantity of caterpillars than others, 

 and keeping each kind by themselves would require an immense 

 number of cages, and much time in changing the food, and paying a 

 proper attention to them. It is a common practice to have a breedmg 

 cage of larger dimensions, by which means a great nimiber of cater- 

 pillars may be fed in one cage, in which a variety of food maj be put, 

 but must be taken away and replaced with fresh plants every second 

 or third day, for this tends greatly to the obtaining of fine specimens 

 of the perfect insect. 



The larvcE of many insects that feed beneath the surface of the 

 earth may be bred in the following manner : Let any box that is about 

 three or four feet square, and two or three feet deep, be lined or co- 

 vered externally with tin, and bore through the sides and bottom a 

 number of very minute holes: put into this box a quantity of earth 

 that is replete with such vegetables as the caterpillars subsist on, and 

 sink it into a bed of earth, so that the surface may be exposed to the 

 different changes of the weather : the lid should be covered with brass 

 or iron net-work, to prevent their escape. 



Cabinet. — In the jnesent advanced state of Entomology, a collec- 

 tion of British insects requires a cabinet of from 60 to 100 drawers, 

 which are generally about fourteen or fifteen inches in length and 

 breadth, and about two inches in depth ; tlie cork with which the bot- 

 toms are to be lined must be chosen as free from cracks and knots as 

 possible, and filed, or cut very level, and be about the sixth of an inch 

 in substance. The top of every drawer must be glazed, to prevent the 

 admission of dust or air ; the glass is usually fitted into a frame of the 

 same size as the drawer, and is made to let in on a rabbet. 



