How to Check "Grease" 



collecting box, which should be as nearly air-tight as 

 you can make it, and lined with sheet cork. Place 

 some freshly pounded laurel-leaves secured in a piece of 

 muslin at one end of your box. The fumes given off 

 by the bruised leaves soon kill the insects. Don't use 

 ammonia for killing butterflies ; it alters their colours, 

 and, in fact, ruins some altogether. Cyanide of potas- 

 sium or laurel-leaves are the best killing agents, and the 

 latter are by far the safest for boys to handle, as cyanide 

 is very poisonous. 



Specially-made entomological pins can be purchased 

 from all dealers in naturalists' requisites. Black 

 enamelled pins are the vogue just now, and they last 

 longer than the silvered or gilt ones, and resist "grease" 

 better. Many insects, you should know, have a small, 

 and some a large, amount of oil in their bodies, which 

 gradually makes its presence seen, first in the abdomen, 

 and later it spreads (if not checked) to the wings. The 

 oil, coming in contact with the white or yellow pin, 

 soon corrodes it through ; the black enamel resists its 

 action longest. Try to check this " greasing " of your 

 specimens on its first appearance on the body, and if 

 you notice it before it has spread to the wings all may 

 be well. Break the abdomen off at once, and drop it 

 into benzine, where you can let it remain a day or two. 

 Then transfer it to a box of fine dry plaster of Paris 

 for another day or so, and you will be surprised how 

 beautiful and clean it will come out. Another hint : 

 Push a little pin into each body when broken off, and 

 attach a white thread to the pin ; now you can do 



B.B. 17 3 



