PEOCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 953 



Zygjenids, etc.). are very tenacious of life and will fly ofi again gaily 

 after a really hard pinch (Plate 153. fig. 1). 



For most insects a killing-bottle is used, made of any tightly- 

 stoi^pered wide-mouthed glass jar which is usually charged with potas- 

 sium cyanide. The jar should have a cork stopper, as a glass stopper 

 is very liable to break either itself or the bottle when clapped to smartly, 

 as is necessary when shaking specimens into the bottle out of glass- 

 bottomed boxes ; and it is more convenient if the cork stopper is fitted 

 into a wooden top (Flate»153, fig. 2). The jar is charged by filling 

 in small lumps of potassium cyanide to a depth of an inch or more 

 (according to the size of the jar) and then filling the chinks between 

 the lumps with dr}- plaster of paris ; a thick mixture of plaster of 

 paris is now made up with a minimum of water and poured over the 

 cyanide to form a smooth layer, which sets hard and keeps it in place. 

 There is always a considerable condensation of water on the inside of 

 a newly-charged bottle and this water requires to be wiped off several 

 times. In damp weather also the cyanide picks up a good deal of 

 water from the air and the surface of the plaster is liable to get very 

 wet. It is as well, therefore, to cover the surface of the plaster with 

 several layers of thick white blotting-paper, which should be renewed 

 when it becomes wet or dirty. 



Some collectors powder the cyanide and mix it with the plaster. 

 But a bottle prepared with lump cyanide and a minimum of water in 

 the plaster, as described above, will last longer. 



For general collecting, it is useful to have at least two bottles, one 

 of which may be reserved for more delicate specimens which are liable 

 to be broken if mixed up with larger ones. 



Killing-tubes, made from a corked glass tube prepared in the same 

 way as a bottle, are also useful for small specimens, and can be carried 

 in one's coat-pocket when a bottle would be unnecessarily cumbrous. 



Besides potassium cyanide, various other killing materials may 

 be used, such as chloroform, benzine, ammonia, etc. In the case of 

 specimens collected in glass-bottomed boxes, for example, one end of 

 a strip of paper dipped in chloroform may be introduced into the box, 

 when the insect is speedily stupefied. Benzine may be used in a similar 

 way and is sometimes used mixed with chloroform. Killing bottles 

 or tubes may also be extemporized by stuffing a wad of tissue ^Japer 

 into the bottom of a suitable bottle or jar and pouiing onto it a few 

 drops of choloroform or benzine or a mixture of both ; a glass tube 

 charged in this manner will remain effective for two or three hours 

 if not left opened too long. 



