The Life of the Fly 



twice as high? Does she fear lest her worms 

 should be bruised by an excessive drop? There 

 is nothing about her to point to anxiety 

 aroused by the length of the shaft. I never 

 see her explore the tube or take its size. She 

 stands on the trellised orifice; and there the 

 matter ends. Can she be apprised of the 

 depth of the chasm by the comparative faint- 

 ness of the offensive odours that arise from it? 

 Can the sense of smell measure the distance 

 and judge whether it be acceptable or not? 

 Perhaps. 



The fact remains that, despite the attraction 

 of the scent, the Flesh-fly does not expose her 

 worms to disproportionate falls. Can she 

 know beforehand that, when the chrysalids 

 break, her winged family, knocking with a 

 sudden flight against the sides of a tall chim- 

 ney, will be unable to get out? This fore- 

 sight would be in agreement with the rules 

 which order maternal instinct according to 

 future needs. 



But when the fall does not exceed a certain 

 depth, the budding worms of the Flesh-fly are 

 dropped without a qualm, as all our experi- 

 ments show. This principle has a practical ap- 

 plication which is not without its value in mat- 

 ters of domestic economy. It is as well that 



334 



