OTHER INSECTS WITHOUT PRESSURE, 153 



in ether, pass into turpentine, in which it may be allowed to 

 remain any length of time. 



To mount the insect, it will be necessary to form some kind of 

 cell upon the glass slips, and this can be easily accomplished as 

 follows : — First take the insect out on a slip of glass, and notice 

 its extreme length and breadth, so as to know the size of the cell 

 required '; also notice the thickness of the insect. Select a piece 

 of glass rather thinner than the thickest part of the object. The 

 insect must now be replaced in the turpentine until all is ready. 

 From the selected piece of glass cut with a diamond two strips, 

 I — 1 6th of an inch wide; place them together, and cut off two 

 pieces one-eighth of an inch longer than the cell required, then 

 cut two more pieces the width of the cell to form the ends. This 

 plan of cutting two pieces together will be found the best, as it is 

 not only necessary to cut the strips from the same piece of glass, 

 but from the same part of it. The mounting medium to be used 

 is balsam in benzole, which should be rather thick, so that it will 

 just drop comfortably from a glass rod, but not so fluid as would 

 be used for mounting in the ordinary way with pressure. Place 

 the insect on a clean slip, and arrange it carefully ; now drop some 

 balsam both on it and around it, and put the slips of glass in a • 

 proper position to form the cell. The balsam between the glass 

 will hold them securely whilst the cell is being filled quite full of 

 balsam. Now place on the cover-glass, which must, of course, be 

 a suitable size and quite clean, and affix one or two spring clips if 

 the mount is a large one. It will often happen that the cell will 

 not be quite full, and that a bubble of air will be enclosed. This 

 can easily be got rid of by opening the cell at the corner with the 

 setting needle, and dropping in some more balsam. By a little 

 dodging, all air-bubbles can be disposed of. Use plenty of 

 balsam, and when all seems to be in a proper position, put aside 

 to harden for a week or more. It will often happen, when taking 

 off the clip, that a bubble of air will run in ; if so, instantly 

 replace the clip, and the bubble will go out again. Now, at the 

 exact spot where the air enters, place a drop of balsam and 

 remove the clip, when, instead of air, balsam will be drawn in, 

 and the slide should again be put aside for a day or two without 

 any clip. 



