ENEMIES OF FLIES 245 



CHAPTER XXV 



ENEMIES OF FLIES 



Certain vertebrate and invertebrate animals eat adult flies 

 or larvae or both, but the destruction wrought by thena is 

 probably insignificant in comparison with that produced by 

 empusa disease, hymenopterous parasites of larvae and cold and 

 inclement weather. 



Adult flies, (a) Invertebrate enemies. 



Flies are caught and killed by various species of spiders, 

 wasps and robber-flies belonging to the family Asilidcs, but their 

 efforts seem to have little effect in reducing the swarms of flies, 

 Howard (1911, p. 82) mentions that in many parts of the 

 United States a small, rather fragile looking centipede, known 

 as Scutigera forceps Raf , which is a constant inhabitant of the 

 houses, lives on house-flies and other insects, and kills large 

 numbers. 



{b) Vertebrate enemies. 



Some of the lizards which are found in houses in tropical 

 countries feed upon flies. Outside houses, toads and birds, 

 especially poultry, when they have access to manure piles, eat 

 large numbers of larvae as well as adult flies. 



Larvce. 



The larvae of certain Caraboeid beetles, especially those 

 belonging to the genera Harpalus, Platyniis and Agonoderus, and 

 certain Rove beetles and their larvae, of the family Staphylinidce, 

 are occasionally found in manure feeding on young fly larvae, 

 but apparently are not greatly attracted to places where fly 

 larvae flourish. 



