90 THE CLASS OF INSECTS. 



up. Glycerine is excellent for preserving the colors of cater- 

 pillars, though the internal parts decay somewhat, and the 

 specimen is apt to fall to pieces on being roughly handled. 



Laboulbene recommends for the preservation of insects in a 

 fresh state plunging them in a preservative fluid consisting of 

 alcohol with an excess of arsenious acid in fragments, or the 

 common white arsenic of commerce. A pint and a half of al- 

 cohol will take about fourteen grains (troy) of arsenic. The 

 living insect, put into this preparation, absorbs about j^yjy of its 

 own weight. When soaked in this liquor and dried, it will be 

 safe from the ravages of Moths, Anthremis, or Dermestes. This 

 liquid will not change the colors of blue, green, or red beetles 

 if dried after soaking from twelve to twenty-four hours. He- 

 miptera and Orthoptera can be treated in the same way. 



A stay of a month in this arseniated alcohol mineralizes the 

 insect, so that it appears very hard, and, after drying, becomes 

 glazed with a white deposit which can, however, be washed off 

 with alcohol. In this state the specimens become too hard for 

 dissection and study, but will do for cabinet specimens designed 

 for permanent exhibition. 



Another preparation recommended by Laboulbene is alcohol 

 containing a variable quantity of corrosive sublimate, but the 

 latter has to be weighed, as the alcohol evaporates easily, the 

 liquor becoming stronger as it gets older. The strongest solu- 

 tion is one part of corrosive sublimate to one hundred of alco- 

 hol ; the weakest and best is one-tenth of a part of corrosive 

 sublimate to one hundred parts of alcohol. Insects need not re- 

 main in this solution more than two hours before drying. Both 

 of these preparations are very poisonous and should be handled 

 with care. The last-named solution preserves specimens from 

 mould, which will attack pinned insects during damp summers. 



A very strong brine will preserve insects until a better liquor 

 can be procured. Professor A. E. Verrill recommends two sim- 

 ple and cheap solutions for preserving, among other specimens, 

 the larvae of insects "with their natural color and form remark- 

 ably perfect." The first consists of two and a half pounds of 

 common salt and four ounces of nitre dissolved in a gallon of 

 water, and filtered. Specimens should be prepared for perma- 

 nent preservation in this solution by being previously immersed 



