MOUNTING INSECTS. 301 



superfluous balsam is cleaned off, and the slide finished in 

 any desired manner." (Science Kecord, ii., 1883, 17.) 



To Render Small Insects or Larvae Transparent. While 

 some dipterous and hymen opterous larvae are naturally 

 transparent, the nervous system can be more clearly brought 

 out by the use of acetic acid, which can be dropped on the 

 object while in the animalcule or live box or on the glass 



slide. 



Glycerine or glycerine jelly is an excellent article for 

 rendering the body transparent, and can be used in observ- 

 ing living Aphides and similar insects, as it renders the 

 chitinous integument more transparent. 



Dr. Looss has found that a solution of sodic hypochlorite 

 (eau de Labarraque) of the druggists, or of potassic hypo- 

 chlorite (eau de Javelh), is a fine solvent for chitin in 

 making microscopical preparations. " The liquid, as 

 bought, completely dissolves, when heated, even the solidest 

 and hardest chitinous parts of insects in a short time, first 

 making them glass-like, transparent, and entirely colorless. 

 If the liquid is diluted with six or seven times its volume 

 of water, and the chitinous parts, either fresh or after they 

 have been hardened, are put in it for twenty-four hours, or 

 even longer according to size, the chitin will be altered, 

 although not noticeably externally; it loses much of its 

 original brittleness, and above all things is more permeable 

 to staining solutions. The objects require for complete 

 staining greater or less time according to size, but the 

 coloration is beautiful and distinct with either alcoholic or 

 aqueous staining reagents. In our institute Pediculidse 

 and Mallophaga have been prepared by this method which 

 show, besides their transparency, complete and clear colora- 

 tion." (Psyche, iv. 286.) This fluid may also be used to 

 make the eggs of insects more transparent. 



Mounting Transparent Aquatic Insects. Mr. 0. Lugger 

 describes a new method of preserving and mounting trans- 

 parent aquatic insects for the microscope. For observing 

 them while alive a common life-cell is all that is required, 



