SANITARY OFFICERS 245 



tips to its wings, and on account of its inferior size 

 is often referred to as a young House Fly. Size in 

 the case of insects that have reached the winged 

 stage, it is perhaps unnecessary to point out, is 

 no criterion of age. This stage reached, growth 

 almost invariably ceases. 



The food of the Blue-bottle or Blow Fly (Calli- 

 phora vomitoria) in its grub stage is very different. 

 It is a flesh-feeder, and its proper mission in life is 

 to clear away those animals that have met with 

 death from old age, disease, or in an encounter with 

 an opponent. That mission is undoubtedly an 

 important and beneficial one for the human race, 

 but when that race takes to storing meat, poultry, 

 and fish in its larders, and the keen senses of the 

 Blow Fly track it to its hiding-place, some fault is 

 found with Nature's arrangements. What seems 

 to be required of Nature to meet the altered con- 

 ditions brought about by civilization is the evolu- 

 tion of a race of Blow Flies that can distinguish 

 between what is common and what is property. 

 The vegetarian comment upon this suggestion 

 would be that it would be more reasonable to give 

 up converting our larders into charnel-houses ! 



The truth is, that what we dub domestic pests 

 are part of the price we have got to pay for our 

 domesticity. All the Kill-that-Fly leagues can do 

 will make no appreciable difference to the fly 

 nuisance ; and probably if we were to pull down 

 our houses and return to the pastoral life of our 

 nomad forefathers we should find we had only 



