PARASITES AND ENEMIES 77 



one for a humble-bee. It is a sinq-ular fact that if 

 one kills a female Volucella she at once commences 

 to lay eggs, and so great is the vitality of the ovi- 

 positing apparatus that on one occasion I found 

 about a dozen eggs had been laid by a female in my 

 cyanide killing-bottle. No doubt if they are stung 

 to death by the humble-bees in their nests they are 

 always able to finish laying their eggs. The eggs 

 are large and hard, and when new laid, like those 

 of many insects, are thinly coated with a glutinous 

 substance, which quickly hardens and fastens them 

 to one another and to the object upon which they 

 are laid. The larvae are of a dirty yellowish-white 

 colour and slightly flattened, and have a tough 

 wrinkled skin ; they have six long spines arranged 

 in a semicircle under the anus, and also two rows of 

 rudimentary spines running the whole length of the 

 body on either side. They attain the large size of 

 f in. to -| in. in length and \ in. in width. They 

 live in the debris under the comb and are said to be 

 scavengers ; they certainly have done no harm to 

 the brood in my nests. 



The larvae of another kind of fly, Fannia, are 

 often found on the earth in the nest cavity. They 

 are considerably smaller than the Volucella larvae ; 

 their colour is dirty brown, and they have two 

 rows of spines running the whole length of the 

 body on either side and two more rows closer 

 together along the top ; at the anal end the 

 spines are longer. These are also scavengers and 

 feed upon excrement. The perfect fly is dull 



