METHOD OF PRESERVING LEPIDOPTERA. 405 



up tlie same surfoce. Upon these simple facts I based plans for the preserva- 

 tion of Liepidoptera as long ago as 18::i8, and since then uo specimen which I 

 have wished to preserve has been touched by Dermestes. 



For collecting insects I have generally found the case described by LeVal- 

 liant, during his travels in South Africa, the most convenient. This principally 

 consists of a box filled with perpendicular slides covered with cork, to which 

 the specimens are pinned, and a horizontal drawer at the bottom to receive any 

 specimens which may be disengaged from the slides during transportation, and 

 thus preventing it from damaging those Avhich remain on the slide. The spaces 

 between the slides being all open below, a single bag of camphor placed in the 

 drawer will diiiuse its vapor through all the compartments, and thus prevent the 

 attack of ants, roaches, and other large insects which prey, especially in tropical 

 countries, on the fresh specimens. By placing the specimens on the perpen- 

 dicular slides, tile-fashion, I have found that double the number could be ac- 

 commodated, while additional security was gained by this arrangement from 

 the danger of the loosening of the pins by the jolting of the box. 



In the preparation for the cabinet I begin by pinning the specimens to be 

 preserved in the order in which they are finally to be preserved on the bottom 

 of a shallow box, lined with a thin layer of cork, or, better, of balsa-wood, which 

 is easier penetrated by the point of the pin. This box must be of precisely the 

 same length and breadth as those which are to form the permanent cases of the 

 cabinet. When the specimens have been ar- 

 ranged in the order to suit the taste, and so that 

 one may not overlap the other, the box, with its 

 contents, is transferred to an oven, which I also 

 invented in 1828 for this special object, but 

 which has since been used, generally by chem- 

 ists and others, for a variety of purposes. It is 

 surrounded and heated by boiling water, the 

 temperature of which is sufficient to kill the 

 eggs and the larvaj of the Dermestes, but is not 

 sufficient to injure the specimens of butterflies, 

 moths, &c. The specimens are kept in this oven 

 several hours, or during the night. (See Fig. 1.) 



After the specimens have been sufficiently 

 baked I lay a clean pane of plate glass imme- Firr \ 



diately over the specimens, which, resting on «• • 



the perpendicular sides of the box, does not touch them. On the upper side 

 of this glass plate, face -down, and directly over the pin securing each specimen, 

 I attach, with fish-glue, (isinglass,) a circular piece of paper, about a quarter 

 of an inch in diameter, containing a printed number. The size of the glass 

 plates which I use, and find most convenient, is eight and a half by ten and a 

 half inches. It is commonly imported, and used for cheap mirrors. It must 

 be cleaned with dilute nitric acid, or the surface will be liable to become foggy 

 in damp changes of weather. 



Next small cylinders of cork of the same diameter as the papers contain- 

 iuf the numbers, and just large enoitgh to support the specimens, are cemented 

 to°the o-lass plate directly on the top of each of the paper numbers. The cement 

 used for this purpose is composed of about equal parts of resin, beeswax, and 

 chrome "-reen, melted, for convenience, over a nursery lamp placed on the table 

 beside me. The pieces of cork are dipped into tin; composition, and while the 

 portion of the latter which adheres is still liquid, they are attached to the glass 

 in their proper positions. 



The next operation is to attach the plate glass to a wooden frame, thus form- 

 ing a shallow box, of which the glass plate Avill be the bottom, having the 

 numbers and cork supports on the inner side. This frame is made of strips of 



