COLLECTING & PRESERVING INSECT LIFE. 413 



A similar ring to tliat just described, but with a 

 shallow net, is used for capturing water forms. 



A killing bottle consists of a jar or bottle with 

 a wide neck, and closed with a cork or glass stopper. 

 Into this bottle is put a mixture of potassium 

 cyanide set in plaster of paris. First a layer of the 

 latter, then cyanide, then another layer, and so on 

 until there are about 2 inches of the mixture in the 

 bottle. Moisture will frequently be found to issue 

 from the surface of this mixture. A small piece of 

 blotting paper placed on the surface will absorb 

 this. Insects placed in this type of bottle die almost 

 immediately. 



A second type of killing bottle is one containing 

 a pad of cotton wool saturated with chloroform. 

 This is useful, but loses its strength readily through 

 contact with the air by the removal of the cork. 



The cyanide bottle has proved the more useful, 

 and is the one generally used. Insects should be 

 removed from the bottle when dead, although they 

 may be allowed to remain for a few hours without 

 any apparent injury. If permitted to remain in the 

 bottle longer they will possibly become discoloured 

 and their beauty will be spoilt. 



After removal the insects in most cases are 

 stretched. For this purpose a stretching board is 

 used. Such a board consists of a piece of soft wood, 

 about f in. in thickness and from 4 in. to 6 in. in 

 width. Down the centre a groove is made a little 

 over Jin. in width. On the surface of the board, 

 and also in the bottom of the groove, a layer of thin 

 cork or cork composition is glued, then over the 



