ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 277 



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 they 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 be-t 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 fine Bristol board, and cut it up into pieces, 

 say 12 lines x 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 preparation 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 cannot of course be placed alongside the insects. 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, a coloured ring can be put round the top object-glass by 

 the turntable in the ordinary way, but except for ornament, is not 

 necessary. The author usually prepares two or three dozen of the 

 cards with one cover-glass on at a time, so as to have them ready for 

 use. The object of letting the dissections harden in the cell, half 

 filled with balsam, is that three or four separate parts may be 

 arranged in the most suitable way in the same cell without fear of 

 their being disarranged or injured when the top cover-glass is put on, 

 while both might happen if the whole operation was performed at once. 



For the examination of the saws, a quarter-inch objective is 

 the best, the teeth, in some cases, are so fine that they are apt to be 

 overlooked if lower powers are used. 



Mounting Butterfly-scales.* — Dr. D. H. Briggs recommends the 

 following process. Dissolve 1 part of Anthony's " French Diamond 



♦ Amer. Mon. Micr. Journ., ii. (1881),p. 227. 



