10 COLLECTING AND PRESERVING INSECTS. 



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 

 remain in this solution more than two hours before diying. 

 Both of these preparations are very poisonous and should be 

 handled with care. The last-named solution preserves speci- 

 mens 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 simple and cheap solutions for preserving, among other 

 specimens, the larvae of insects " with their natural color and 

 form remarkably perfect." The first consists of two and a 

 half pounds of common salt and four ounces of nitre dis- 

 solved in a gallon of water and filtered. Specimens should 

 be prepared for permanent preservation in this solution by 

 being previously immersed in a solution consisting of a quart 

 of the first solution and two ounces of arseniate of potash and 

 a gallon of water. 



The nests, cocoons, and chrysalides of insects may be pre- 

 served from injury from other insects by being soaked in the 

 arseniated alcohol, or dipped into benzine, or a solution of car- 

 bolic acid or creosote. 



Dr. J. L. Leconte has published in the ''American Natural- 

 ist," iii, p. 307, some new directions for the preservation of 

 insects which will apply to beetles as well as other insects. 

 " Surgical art has given to us an instrument by which a poison- 

 ous liquid can be rapidly and most effectively applied to the 

 entire surface of large numbers of specimens as they stand in 

 the cabinet boxes, without the trouble of moving them. I re- 

 fer to the ' Atomizer.' 



"Opinions may vary as to the nature of the liquid poison to 

 ]>e used, but after several trials I have found the following 

 formula to be quite satisfactory ; it produces no efflorescence, 

 even on the most highly polished species, while the odor is 

 quite strong, and persistent enough to destroy any larvae or 

 eggs that may be already in the box: — saturated alcoholic 

 solution of arsenious acid, eight fluid ounces ; strychnine, 



