MOUNTING APPENDAGES OF INSECTS. 323 



Mounting Dry the Eggs of Insects. According to Dimmock, eggs 

 and other objects may be mounted in such a way as to be easily ex- 

 amined with the microscope. The eggs are mounted in rings of 

 cork between two thin cover-glasses such as are used for micr-oscope- 

 slides. Thus mounted, and sealed with black lac or other means, 

 the specimens can be pinned in the collection with safety and neat- 

 ness. Specimens can be mounted in Canada balsam in these cork 

 rings in the way described by Cameron,* who, however, used paper 

 in place of cork; the latter, however, is lighter than paper, is more 

 convenient for pinning, and can be easily cut into rings of different 

 sizes with a cork-borer such as is used in chemical laboratories. If 

 circular cover-glasses are used, the cells can be neatly sealed on a 

 turn-table for preparing microscope-slides. (Psyche, iv. 133.) 



Preparing Fire flies, etc. To investigate the seat of oxidation 

 which produces the light in Luciola italica, Dr. C. Emery killed the 

 living animal in a solution of osmicacid, which stains the luminous 

 plates of the still living and light-developing animals brown. The 

 parts which are to be further examined are macerated for a long 

 time in water, the development of fungi in which is prevented by 

 the addition of crystals of thymol. The osmic acid is especially re- 

 duced at the bifurcations of the blind-ending tracheal capillaries 

 within the luminous plates, and in the tracheal branches before the 

 bifurcation. Another method of preservation consists in injecting 

 corrosive sublimate solution into the animal, and subsequent treat- 

 ment with alcohol. (Zeits. filr wissen. Zoologie, xl. (1884) 338 ; ab- 

 stract in Journ. Roy. Micr. Soc., 1885, 733.) 



Mounting the Appendages of Insects for Pinning in the Cabinet. 

 A writer in the Bulletin of the Brooklyn Entomological Society (vi. 

 24) says: " The habit of many has been after examining the parts of 

 an insect and making dissections to throw away the insect after 

 making notes. Others mount them in balsam on glass slides: this 

 latter had been my practice, but slides accumulate and are incon- 

 venient to keep. A substitute a knowledge of which I owe to Dr. 

 Horn answers admirably for all purposes and is perfectly simple. 

 A hole, round or square, is punched or cut out of a piece of Bristol 

 board of any desired size; a cover-glass (I use the square) is fastened 

 on one side over the aperture by a thin circle of shellac: this forms a 

 shallow cell in which the part to be examined is placed; a drop of 

 Canada balsamf is put on it, and the whole is covered by another cover- 



* Proc. Nat. Hist, Soc. Glasgow, 1881-82, y. 4-7. 



f The balsam will be clouded by the moisture contained in the 

 appendages unless it has been macerated in alcohol and oil of 

 turpentine, or has undergone a long maceration in oil of turpentine. 



