66 the taxtpe^iist's guide. 



Several of the Moth tribe are extremely liable to change their 

 color some time after they have been placed in a cabinet. This 

 change is frequently occasioned by an oily matter which is common 

 to many of them. This first makes its appearance in small spots 

 on the body, but soon spreads itself over the abdomen, thorax, 

 and wings ; and ends in a total obliteration of all the beautiful 

 markings. A method which has been sometimes successfully 

 adopted is to sprinkle all the wings with powdered chalk, and 

 holding a heated iron over it ; the chalk absorbs the grease, and 

 may then be blown off by means of a pair of small bellows. 

 Another way of applying the chalk, and perhaps the better of the 

 two, is to throw some powdered chalk on the face of a heated 

 iron, and then put it into a piece of linen cloth, and apply it to 

 the body of the insect ; the heat of the iron will soften the grease, 

 and the chalk will absorb it. 



Another method is to hold a heated iron over the insects for a 

 few minutes, and then to wash the spotted or greasy places with 

 ox gall and water, applied with a camel-hair pencil, and afterwards 

 wash it with pure water, and dry it by an application of blotting 

 paper, and when perfectly dry imbue it with the solution of cor- 

 rosive sublimate. But grease seldom appears where the contents 

 of the abdomen have been removed. 



Orders Neuroptera, Hymenoptera, and Diptera. — The 

 Dragon-Flies (Libellula) are frequently very difficult to kill, being 

 powerful and nervous animals. When caught they should be 

 transfixed through the sides, and it sometimes becomes necessary 

 to put braces on their wings to prevent them from fluttering while 

 in the hunting box. They may also be killed sometimes by placing 

 them under a tumbler and suffocating them. Some Entomologists 

 put them in scalding water for an instant. 



* The contents of the abdomen should always be removed from 

 Dragon Flies, otherwise it will become black and shining through 

 the skin, and destroy the beautiful bands with which they are 

 ornamented. They can be stuffed with cotton or a small roll of 

 paper introduced. If these precautions are attended to, the insect 

 will preserve the perfect beauty of its living state. 



The other species of these Orders soon die after ^eing trans- 

 fixed. They may be set by braces and pins, as represented in 

 figures 35 and 37. 



