124 BEES AND WASPS [OH. 



drawer of the cabinet a small piece of sponge soaked 

 in carbolic acid, and by keeping plenty of naphthaline 

 in each. A wash of dilute formalin painted all over 

 the inner surface of the drawer and allowed to dry 

 before any insects are placed in it is also very 

 effective. 



If it is desired to add to the collection the nests 

 of such species as construct nests capable of preser- 

 vation, it is necessary thoroughly to desiccate the 

 whole structure so as to shrivel up and sterilise all 

 organic matter that may be still within the cells. 

 This process may be accomplished by placing the 

 nest in an open wooden box metal is too good a 

 conductor of heat and may lead to charring of the 

 parts in contact with it in a moderately warm 

 kitchen-oven after the culinary operations of the 

 day are completed. In the case of wasps' nests the 

 required temperature is higher than might be ex- 

 pected; for the wrappings of the nest include so 

 much air that the central parts of the nest, i.e. the 

 combs containing the larvae, pupae, and young wasps 

 just ready to emerge, do not receive anything ap- 

 proaching the actual temperature of the oven for a 

 very long time. Should the temperature be insuffi- 

 cient to kill the young wasps, the collector may be 

 disagreeably surprised, as I was on one occasion, on 

 opening the oven door, to fin<,} a large number of very 

 lively young wasps crawling over the nest and flying 



