300 INSECT LIFE. 



In this way there is but little danger of bending 

 the pin. 



Preservative Fluids. — The most important of 

 the preservative fluids is alcohol, and, except for 

 special purposes, no other is needed. The alcohol 

 should be of the full strength of ordinary commercial 

 alcohol — i. e., ninety-five per cent. It should be 

 noted, however, that many soft-bodied insects, espe- 

 cially larvas, shrivel if put directly into strong alcohol ; 

 with these it is necessary to remove the water from 

 the body gradually. This can be done by placing 

 the specimens in alcohol of different strengths suc- 

 cessively, using at first fifty per cent alcohol. This 

 can be easily prepared by half filling the bottle with 

 strong alcohol, then nearly filling it with water, and 

 shaking it a few times. The specimens should not 

 be left more than five or six hours in this ; they 

 should then be transferred to seventy-five per cent 

 alcohol, prepared in a similar way. They may be 

 left in this for one day, and then transferred to 

 strong alcohol for permanent preservation. 



Certain colorless or white grubs and maggots are 

 apt to turn black when preserved in alcohol. This 

 can be prevented by first dipping them in boiling 

 water for a few seconds, after which they should be 

 placed in alcohol as described above. 



Mounting Microscopic Objects. — Insects that 

 are too minute to be pinned or satisfactorily mounted 

 on cardboard points are usually mounted in Canada 

 balsam on a glass slide, and covered with a very thin 

 sheet of glass. The slides, balsam, and cover-glasses 

 can be obtained of any dealer in optical apparatus. 



In most cases it is necessary to remove the water 



