CHAPTER XXVI. 



SOME INSECTS OF ECONOMIC IMPORTANCE. 



FLIES OP THE FARM. 



AMONGST the insects abounding in the neighbourhood of 

 cultivated fields or domestic animals, flies are probably of 

 chief importance. From the characters given on p. 168 it 

 will not be found difficult to distinguish flies from all other 

 insect types. 



In general it ought to be noted that flies are of con- 

 siderable economic importance everywhere. Mosquitos, 

 so abundant all over the world, are important as trans- 

 mitters of malaria ; tse-tse flies in Africa communicate the 

 dread disease of sleeping sickness as well as analogous 

 diseases to domestic animals ; the house fly, although not 

 a biting fly, from its indiscriminate visits to all sorts of 

 places and substances, including human food, is an ever 

 present danger to health. 



We shall not here attempt to enumerate more than a 

 few of the flies which may be in evidence on the farm in 

 the warmer seasons of the year. And we shall classify 

 them according to their habits. 



1. Biting Flies, i.e. Blood-sucking. f 



(a) The Stable fly. Superficially very like the house fly, 

 and so termed by the uninitiated. It is most readily dis- 

 tinguished from house flies by having a black slender pro- 

 boscis projecting in front of the head and visible from 

 above. This is the blood-sucking organ. It is common, 



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