The Life of the Fly 



through a thin crevice, hardly reaches my 

 nostrils. 



They explore the metal receptacle for some 

 time, seeking an entrance. Finding naught 

 that enables them to reach the coveted morsel, 

 they decide to lay their eggs on the tin, just 

 beside the aperture. Sometimes, when the 

 width of the passage allows of It, they In- 

 sert the ovipositor Into the tin and lay the 

 eggs Inside, on the very edges of the slit. 

 Whether outside or In, the eggs are dabbed 

 down In a fairly regular and absolutely white 

 layer. I as It were shovel them up with a 

 little paper scoop. I thus obtain all the germs 

 that I require for my experiments, eggs bear- 

 ing no trace of the stains which would be In- 

 evitable If I had to collect them on tainted 

 meat. 



We have seen the Bluebottle refusing to lay 

 her eggs on the paper bag, notwithstanding 

 the carrion fumes of the Linnet enclosed; yet 

 now, without hesitation, she lays themi on a 

 sheet of metal. Can the nature of the floor 

 make any difference to her? I replace the tin 

 lid by a paper cover stretched and pasted over 

 the orifice. With the point of my knife, I 

 make a narrow slit In this new lid. That is 

 quite enough : the parent accepts the paper. 

 328 



