ON COLLECTING, PREPARATION, AND MOUNTING. 381 



touch the boiling-water, many of them will immediately spread out 

 their wings in the correct position for setting, in fact, appearing 

 perfectly set on the surface of the water. Select the best-looking ones, 

 and float each insect on to a separate microscopical cover-glass, and then 

 place the wings, antennae, and legs in the correct position : remove 

 the moisture by means of clean blotting-paper, and then drop methyl- 

 ated spirits on to the insect : lay them aside, and cover them over 

 with a large inverted glass, a large champagne-glass which has its 

 foot broken off is a very good thing for this. We have then the 

 insects well set either for microscopic slides or cabinet specimens ; 

 and it may be noted that the principle of the method adopted is to 

 make the delicate insects as far as possible set themselves. 



If specimens are intended for the microscope, it will be necessary to 

 place the insect on the cover-glass with the under surface upwards, 

 place on it a drop of absolute alcohol, and allow it to evaporate under 

 the bell-jar glass, which, by the way, should be so arranged as to 

 allow a little air to enter from below. When the alcohol has evapor- 

 ated, it will be found that the insect adheres firmly to the cover-glass, 

 and when in this condition, immerse it in oil of cloves for twelve 

 hours, and again remove the surplus oil of cloves with blotting-paper. 

 Then place a drop of xylol or benzole, according to the balsam which 

 is used, and allow this partially to evaporate; then place a drop of 

 balsam on the insect again, allow it to stand for, say, twenty-four 

 hours under the bell-jar ; prepare a microscopic slip in the usual way, 

 place a drop of balsam on the centre of the slip, and then turn over 

 and press the previously prepared insect on the cover-glass into the 

 balsam on the slip. We have then a well -mounted slide for ordinary 

 purposes. 



If, however, a more transparent object is desired, the following 

 method may be adopted : Prepare the insect as previously described, 

 and when it is well set on the cover-glass and thoroughly free from 

 moisture, separate it from the cover-glass and place it in liquor- 

 potassa?. It should be borne in mind that when well set in this 

 way, the insect will, with careful handling, always remain in this 

 fixed position. Hence it may be allowed to remain in the liquor- 

 potassse for one or two days, then float it on to a cover-glass, 

 and place it (by careful floating) on to clean water. Thus it may 

 be gradually washed in this way in water, alcohol, and xylol re- 

 spectively, until quite transparent. Then float it on to oil of cloves 



