xxxiii, '22] ENTOMOLOGICAL NEWS 113 



some set the same day as caught and many at a later date after 

 the usual relaxing process, and have had practically no trouble 

 from stiff wings. 



In making up the killing bottle use a piece of felt at least 

 a quarter of an inch thick. It can be bought under the name 

 of laundry felt or moulder's cloth. It should be cut so as 

 to make a tight fit in the bottom of the bottle. This can be 

 done by the cut and try method, leaving the felt slightly larger 

 than the inside diameter of the bottle so that it has to be forced 

 down into place. The felt will then be tight and will not fall 

 out Avhen the bottle is inverted. Over the felt place a piece 

 of cotton to the depth of at least one inch. In making this 

 mat of cotton care should be taken that it makes a fairly tight 

 fit against the sides of the bottle and that the edges are not 

 rounded downward. This is important for if rounded, small 

 specimens slide down, become wet with the tetrachloride and 

 stick to the Hass and mav be ruined in trying to remove them. 

 The tetrachloride itself does not seem to harm the specimens. 

 In pouring the tetrachloride, slightly part the cotton from the 

 glass, using a pencil, as one is usuallv at hand, and pour the 

 fluid down the c ide into the felt without wetting the cotton, 

 tipniner the bottle sliehtlv to one side in the meantime. 



The bottle properly prepared. /. c., with the felt well wet, 

 will last at least one dav in active service. I used to carrv a 

 small bottle of the fluid in the field in order to recharge, but 

 found that that was not necessary. The bottle when corked, 

 will keep for months. The carbon-tetrachloride can be bought 

 at any chemist's and there are also some cleaning fluids such 

 as Carbona which seem to be composed largely of it and 

 which answer the purpose perfectly. 



The carbon-tetrachloride would seem to lend itself easily to 

 other methods of killing insect and other pests, due to its 

 extremely heavy vapor and absolute fire-proof quality, and 

 we may expect development along this line in the future. 



\Notc. Very frequently boys and girls wish to collect insects and 

 it has not been considered safe or wise to allow them to use cyanide 

 bottles. At present it is difficult to purchase small quantities of 

 cyanide, on account of the regulations in regard to the sale of poisons. 

 Carbon tetrachloride would supply a harmless preparation for both 

 children and adults. For certain insects that have long tarsal claws. 

 it would be necessary to put something smooth over the cotton, with 

 perforations, if mvrssary, to permit the gas to escape into the bottle. 

 H. S.] 



