324 ENTOMOLOGY. 



glass. Your preparation is thus effectually preserved, and you can 

 put a pin through the end of the card and put it in your cabinet next 

 the insect the object is intended to illustrate. You can put half a 

 dozen cards on a single pin, and the space thus occupied is very small, 

 while the preparation is as convenient for examination as though 

 mounted on a glass slide." 



Mounting the "Saw" of the Tenthredinidae. Mr. P. Cameron 

 describes his method of mounting and preserving the "saw" of the 

 Tenthredinidoe for microscopical examination, a method which can 

 be applied to microscopical mounting generally. 



With fresh specimens the saws can be extracted by pressing the 

 abdomen, when they will be protruded and readily extracted. With 

 old specimens it can be done equally well by placing the insect in a 

 relaxing-dish, or, more promptly, by steeping it in water for a day, 

 when it can be taken out in the same way as with fresh insects, 

 the only difficulty being experienced with insects full of eggs. For 

 their better examination the four pieces composing the ovipositor 

 proper should be separated; after which they must be steeped in 

 turpentine for a day or two so as to get rid of air. This is best done 

 by enclosing them in a small folded piece of paper; and, if they be 

 properly labelled, many different preparations can be placed in the 

 turpentine-bottle together. Next take a sheet of tine Bristol board, 

 and cut it up into pieces, say 12 lines by 9 lines, and punch at one 

 end a round or square hole, four or five lines across. On the lower 

 side of this fasten, by means of Canada balsam dissolved in benzine, 

 a cover-glass. When this has dried fill up half the cell thus formed 

 with the same composition, spreading it as evenly as possible, and in 

 it arrange your preparation. Put it aside for some hours in a place 

 where no dust will fall on it, then fill the cell with enough balsam 

 to run over the edge of the cell, place a cover-glass over it, and press 

 it down. All that now requires to be done is to allow the prepara- 

 tion to dry, taking special care to keep it flat, to label it, and stick a 

 pin through the card, by means of which it is fixed in the cabinet 

 alongside the insect from which the part was taken. To examine it 

 under the microscope, all that is necessary to do is to place an 

 ordinary glass slide across the stage, and put the card on it, in doing 

 which it is not necessary to take the pin out of it if a short pin be 

 used. 



The great advantage of this plan for entomological purposes is that 

 it does not necessitate the formation of two distinct collections, which 

 must be the case if dissections are mounted on glass slides, which can- 

 not of course be placed alongside the insect. Besides that, it is cheaper, 

 more expeditious, and safer; for the cards are so light that no injury 

 comes to them from falling, or getting loose in the box. If desired, 



