308 ENTOMOLOGY. 



with just sufficient water added to keep it fluid) on a slide, and drop 

 into it the living insect; it will be seen to struggle for a second or 

 two, then the limbs, wings, and tongue become extended; it then 

 becomes beautifully clear and transparent. The acid should now be 

 drained away, a drop of balsam put on, the cover applied. ..." 

 (North. Microscopist, ii., 1882, 227.) 



Bleaching Fluid for Insects. W. Sargent recommends the follow- 

 ing: Hydrochloric acid, 10 drops; chlorate of potash, |dr. ; water, 

 1 oz. Soak the insect in it for a day or two, then wash well. (Journ. 

 R. Micr. Soc., 1883, 151.) 



To Clear Objects for Balsam Mounting. Dr. J. J. Mason uses a mix- 

 ture of carbolic acid, one part, and oil of turpentine, four parts, 

 mixed. When the object is perfectly clear, drain off the superfluous 

 mixture and mount in balsam. 



Mounting Insects in Balsam without Pressure. Mr. H. Chadwick 

 gives the following directions : 



Preparation. I. Soak the specimens in liquor potassae until they 

 are transparent. Wash well in distilled water, using a pipette and 

 camel-Jiair pencil. Transfer to 50 per cent spirit, then to a small 

 quantity of pure spirit in a watch-glass or soakiug-bottle, and allow 

 them to macerate. By this method the formation of air-bubbles in 

 the interior of the specimens may generally be avoided. 



II. Wash well in distilled water. Soak in pure spirit or alcohol 

 for some days. Transfer to carbolic acid until sufficiently trans- 

 parent. Then transfer to oil of cloves, but many persons do not 

 consider this necessary. This method should be used in all cases 

 where the integument is too opaque to allow light to pass through 

 it before treatment, and it is especially useful in the study of the 

 muscles. 



Mounting. Take a clean 3x1 slip, having a sunken cell in its 

 centre. Just inside the edge of the cell, equidistant from each 

 other, cement three white glass beads with hardened balsam. Put a 

 small quantity of soft balsam in the centre of the cell, and gently 

 warm it over a spirit-lamp. Take the object, a wasp's or blow-fly's 

 head, for example, and place it upon the previously warmed balsam, 

 arranging it in the required position. Now take a clean cover-glass, 

 the diameter of which should be a little less than that of the cell, and 

 holding it between the points of a pair of forceps, place a large drop of 

 balsam in its centre, and allow it to fall upon the object. The edge 

 of the cover should rest upon the three beads. If the quantity of 

 balsam under the cover-glass is not sufficient to fill up the whole of 

 the space between it and the slide, a little more must be allowed to 

 run in, and if the object has become displaced, it maybe rearranged 

 by means of a fine blunt needle, introduced beneath the cover-glass. 



