256 ENTOMOLOGY. 



After some practice in rearing larvae it will be found easier 

 and more profitable to search for the leaf-miners, and rear 

 the perfect, fresh, and uninjured moths from them. In this 

 way many species never found in the perfect state can be 

 secured. * 



In raising Micro larvee it is essential that the leaf in 

 which they mine be preserved fresh for a long time. Thus 

 a glass jar, tumbler, or jam-pot, the top of which has been 

 ground to receive an air-tight glass cover, and the bottom 

 covered with moist white sand, will keep a leaf fresh for a 

 week, and thus a larva in the summer will have to be fed 

 but two or three times before it changes ; and the moth can 

 be seen through the glass without taking off the cover ; or 

 a glass cylinder can be placed over a plant inserted in wet 

 sand, having the top covered with gauze. Dr. H. Gr. 

 Knaggs, in treating of the management of caterpillars in 

 breeding-boxes, enumerates the diseases, besides muscar- 

 dine and cholerine (and we might add pebrine), to which 

 they are subject. Among direct injuries are wounds and 

 bruises, which may be productive of deformities in the 

 future imago ; the stings of ichneumon flies, whose eggs 

 laid either upon or in the body may be crushed with finely 

 pointed scissors or pliers ; frost-bites ; and suffocation, 

 chiefly from drowning. If the caterpillar has not been 

 more than ten or twelve hours in the water, it may be re- 

 covered by being dried on a piece of blotting-paper and ex- 

 posed to the sun. Larva? may also starve to death, even 

 when food is abundant, from loss of appetite, or improper 

 ventilation, light, etc. ; or they may eat too much, become 

 dropsical and die. Caterpillars undoubtedly suffer from a 



* " In general, it may be said, the mines of the leaf -miners are 

 characteristic of the genus to which the larva may belong. A 

 single mine once identified enables the collector to pronounce on the 

 genus of all the species he may rind thereafter. This, added to the 

 ease with which the larvae are collected, and the little subsequent care 

 required to bring them to maturity, except to keep the leaves in a 

 fresh and healthy state, makes the study of this group, in every respect, 

 pleasant and satisfactory to the entomologist." (Clemens.) 



