42 THE FLY'S ENEMIES 



difficult to say whether these are friends or enemies or 

 merely hangers-on. They have been known a long 

 time, for, according to Howard, Dr. Geer mentioned 

 mites attaching themselves to flies in 1755, and Linnaeus 

 wrote about them in 1758. The most common of 

 these parasites are the cheese-mites. The mite clings 

 to the fly and drops off on to a new cheese. Here it 

 breeds with great rapidity in warm weather ; but when 

 it is cold its life, like that of its host, is slowed but 

 prolonged, and so is that of the cheese. Then there 

 are red mites, which attach themselves to flies as they 

 do to mosquitos. They cling on between the legs of 

 the fly. But whether they kill the flies or not is not 

 known. 



Some spiders catch flies in their nets ; then they 

 kill and eat them. But spiders, even in the most 

 cobwebby houses, cannot account for many flies. Like 

 the mites and ants, their share in fly-reduction is small. 

 There are also scorpions and centipedes, lizards and 

 chamelions, which kill flies, and rats and even dogs will 

 catch flies ; and there are some microscopic parasites, 

 protozoa, which inhabit house-flies, namely, Herpe- 

 tomonas muscce domesticce, 1 and, according to Captain 

 Patten, another flagellate parasite, resembling the 

 Leish?na?iia, is found inside house-flies in India. 



But the fly's greatest enemy is, or should be, man. 

 Conversely, the fly is one of man's greatest enemies. 

 The feud is one which must last as long as one or the 

 other endures. It is an eternal war between the insects 

 and the human beings, for Nature has ordained a 

 vendetta between man and the most puny-looking yet 

 one of the most powerful of his antagonists. Like all 



1 According to Colonel Jennings, L.M.S., this parasite is only found in 

 the male flies, which is an interesting thing. 



