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terrible elephantiasis, is due to more than one species of gnat 

 or mosquito. It is true that no one has ever seen the actual 

 transference of the Filaria from the biting organs of the Culex, 

 Anopheles, Panoplites, or Stegomyia into the human body, but 

 the circumstantial evidence is so strong that on it any jury 

 would convict. Noe and Grassi have demonstrated a similar 

 mode of infection for the Filaria immitis, which exists, in the 

 adult stage, in such incredible numbers in the cavity of the 

 right side of the heart of dogs, especially in tropical and in 

 sub-tropical countries, that it is difficult to see how the circu- 

 lation can be maintained at all. It is therefore interesting to 

 note that the proboscis of our common house-fly frequently 

 harbours a larval nematode which has been described by 

 Carter 1 under the name of Habroncma mnsca? ; and again 

 (if it be the same species) by Generali 2 under the name 

 Nematodum sp. (?) ; and again by Piana, 3 who is inclined to 

 think it is the larval form of Dispharagus nasutus (Rud.). What 

 the further history of this parasite is we do not conclusively 

 know ; but judging by analogy — and in the case of the grosser 

 parasites it is not always wise to do that — the nematode 

 probably develops in some higher animal which eats the fly. 

 Piana brings forward a good deal of evidence that this is the 

 domestic fowl. 



Another parasite which attacks flies is the fungus or mould 

 Empusa musca?, whose growth is fatal to the insect. The hyphae 

 penetrate into the body, and, as they grow, weaken the fly until 

 it is unable to lift a leg, but remains glued by its viscid feet 

 to the object upon which it rests. The fungus spreads and 

 radiates out in all directions, covering the fly as with a velvety 

 pile, and giving off countless minute spores, which are blown 

 away to alight, if they are lucky, on a further victim. 



I think enough has been said to prove that flies are a very 

 real danger to our community. I have refrained from giving 

 the appalling statistics of our infant mortality, partly because of 

 the difficulty of discriminating between the claims of the flies 

 and those of other agencies which affect the lives of our babies — 

 e.g. the insurance companies which do a large trade in 

 insuring infants. Legislation has not attempted to control the 



1 Ann. Nat. Hist., ser. 3, vii. p. 29. 



2 Atti Soc. Modena, ser. 3, ii. Radiconte, p. 88. 



3 Atti Mus. Milano, xxxvi. 1896, p. 239. 



