THE PRESERVATION OF SPECIMENS. 



309 



Hooks are usually put on insect cases, as shown 

 in Fig. 277, but they are hardly necessary on small 

 cases if they are made so that the covers fit tightly. 



Insect cases are usually left the natural color of 

 the wood on the outside and painted white on the in- 

 side. Ordinary oil paint is not suitable for this, as it 

 will turn yellow when kept in the dark. The best 

 paint for this purpose is made of zinc-white and glue. 

 Care should be taken to get the best quality of zinc- 

 white — that which is free from lumps — otherwise a 

 smooth paint can not be made. 



In making this paint use an ordinary glue-pot. 

 Dissolve one part by weight of glue in five parts of 

 water. Then stir in zinc-white until the mixture is 

 of the consistency of ordinary paint ; about five parts 

 by weight of zinc-white will be required. The mix- 

 ture is heated while being prepared, and is used 

 warm. If any of the mixture is left unused it forms 

 a solid cake ; but this can be liquefied by heat and 

 used when desired. This paint dries in a few min- 

 utes after being applied, and will remain permanently 

 a beautiful, clear white. 



It is very desirable, if practicable, to have the 

 cases lined with cork. Sheet-cork is kept by the 

 dealers in entomological supplies for this purpose, 

 and recently compressed cork, which, when well 

 made, is better than sheet-cork, has come into use. 

 Compressed cork is ground cork mixed with a small 

 amount of glue, compressed into sheets, and covered 

 with paper. As a single sheet of compressed cork 

 will cover the bottom of the case, it presents a 

 neater appearance than sheet-cork. Thick linoleum, 

 a substance made of cork and used for covering 



