ENTOMOLOGICAL INSTRUMENTS, &C. 559 



dead insects, you will of course wish to know how they 

 may be kept out of your drawers, or banished when de- 

 tected there. Camphor is the general remedy recom- 

 mended. The cavity closed by the rabbet of the glass 

 frame affords a good receptacle for this necessary article : 

 put some roughly powdered into each side, and be care- 

 ful to renew it when evaporated. This will generally 

 preserve your insects, as will be seen from the result of 

 the following experiment. Some insects in a chip box 

 having become much infested by mites and Psocus pul- 

 satorius, I placed under a wine-glass several of each 

 along with roughly-powdered camphor : at the end of 

 twenty-four hours the mites were alive ; but at the end 

 of forty-eight they were all apparently dead, and did not 

 revive upon the removal of the camphor. The speci- 

 mens of Psocus all appeared dead in an hour, and never 

 revived. If the camphor be put only into one side of a 

 drawer, and in a lump, though perhaps it may keep out 

 mites, &c., it will not expel them. 



I am, &c. 



