THE PREPARATION OF MATERIAL. 283 



VII. On Mounting Insects. 1 A few simple directions will be suffi- 

 cient guide to the preparation of the few life-history boxes men- 

 tioned in this book. The steps in the process are (1) the fixing of 

 the specimens on pins ; (2) the thorough drying of them ; and (3) 

 the mounting of them, under glass, in a box of some sort, tightly 

 sealed to keep out pests. 



Most specimens may be fixed on pins run vertically through the thorax 

 two thirds of their length. Beetles (with wings closed) should have 

 the pins run through the center of the left wing cover, and obliquely 

 downward through the body. Minute specimens may be fixed with 

 mucilage on a narrow strip of white paper, through which the pin 

 may be stuck. Pins of uniform length (preferably insect pins) should 

 be used, and the mounted specimens should stand at the same height 

 on all the pins. When the wings of an insect are to be spread and 

 dried so, a setting board is necessary. The pin is run through the 

 insect in the usual way. The body is placed in a groove in the set- 

 ting board, and the wings are spread horizontally upon the board, and 

 held in position by strips of paper pinned across their tips. 



The best boxes for preserving insect specimens are lined on the 

 bottom with sheet cork, into which the pins can easily be pushed. 

 Thin disks, 'of uniform size, cut from common bottle corks, and 

 glued to the bottom of the box, will generally answer the student's 

 purpose. A bit of gum camphor should be placed in the box, and 

 the top and all cracks tightly sealed, if the preparation is to be per- 

 manent. 



VIII. On Dissecting under Water. Small animals not covered with 

 hair or feathers are best dissected under water. Delicate parts are 

 floated into view, and more easily separated and more easily recog- 

 nized under water. 



Excellent dissecting pans are made by pouring melted wax or 

 paraffin e into a shallow vessel to harden on the bottom and form a 

 thin layer, to which the specimens may be pinned down. A piece of 

 thin board wedged fast in the bottom of a pan with vertical sides 

 will answer every purpose. 



The structure of small parts may often be better made out by " teas- 

 ing"; i.e., by tearing apart with needles on a slip in a drop of water, 

 or, better, of dilute glycerine. 



1 Part F of Bulletin No. 39, United States National Museum, entitled 

 Directions for Collecting and Preserving Insects, contains full and explicit 

 directions, as well as a fund of suggestions, as to methods of rearing insects, 

 references to entomological literature, etc. It may be had for the asking, and 

 a copy should be in every school library. 



