HOUSEHOLD AND CAMP INSECTS 9 



excessive moisture and are found only in the dryer portions of 

 manure heaps. It is stated that while this insect breeds in large 

 numbers in stable refuse stored close to buildings, the open pile 

 located far from houses is but little frequented by house flies. ^ It 

 is possible that the state of fermentation is more important than 

 proximity to dwellings or other shelters, though the latter doubtless 

 have an influence. The maggots thrive only in certain portions of 

 the manure pile, namely, in a layer some inches deep and lying a 

 few inches below the surface where there may be found a moderate 

 amount of heat and moisture, an excess of either being fatal or 

 compelling migration. They can exist to only a relatively slight 

 depth in well-packed manure.^ It has been shown that 98 to 99 

 per cent of the maggots occurring in manure can be driven out, 

 provided there is sufficient moisture. ^° The full-grown larvae (at 

 least 70 per cent) prior to changing to the resting or pupal stage, 

 desert the earlier habitat for dryer portions of the pile, or may 

 leave it entirely and transform in the soil a foot or two away. 



The investigation of fly conditions in a western city resulted in 

 trapping approximately 96,000 flies representing some 25 species, 

 over 88,000 being house flies. The others present in greatest num- 

 bers were Muscina stabulans, Lucilia sericata 

 and Phormia. Probably 90 per cent of the flies taken on garbage 

 were house flies, while of those captured in the open with human 

 excrement as a bait, nearly 21 per cent were various species of 

 flesh flies or sarcophagids.^^ 



The favorite breeding place of the house fly is horse manure, 

 though cow manure, especially if there be present a little straw or 

 ensilage, may prove to be an important breeding medium. Chicken 

 manure is an acceptable breeding place when moist. ^^ Flies were 

 reared in large numbers from waste ensilage, and infestation also 

 occurred in the silo, especially near the edge where decomposition 

 had begun. It was not necessary that the material be soaked with 

 urine.^^ 



Garbage produced 22 per cent each of the house fly and 

 Phormia regina, 50 per cent Lucilia sericata, and 

 some other flies at Boston, Mass.^* 



8 Eltringham. Jour. Agr. Sci., Cambridge : 7 :443-57. 1916. 



9 Hewitt. Jour. Econ. Ent., 7 :28i-89. 1914. 



10 Hutchinson. U. S. Dep't Agr. Bui. 14. 1914. 



11 Parker. Mont. State Bd. Ent, ist Rep't, p. 38-50. 1914. 



12 Richardson. N. J. Agri. Exp. Sta. Rep't, p. 382-99. 1915. 



13 F. B. Milliken. Jour. Econ. Ent, 4 •275- IQH- 



14 Paine. Psyche, 19:156-59. 1912. 



