Vol. xxviii] ENTOMOLOGICAL NEWS. 281 



to seek the warmth inside houses and to remain there for com- 

 paratively longer periods than earlier in the season. From 

 this time on flies become fewer and fewer, though they are 

 frequently seen in houses during warm spells as late as De- 

 cember. Observations made in a greenhouse at Bozeman dur- 

 ing the winter of 1916 and 191 7 indicate that the winter is 

 sometimes passed by continuous breeding in warm places af- 

 fording suitable conditions. It is probable that the flies also 

 winter over in the pupal state. At Miles City (altitude 2200 

 ft.) house flies begin to be numerous early in May, later in 

 cities in higher altitudes. 



The house fly constituted 91.80 per cent, of the total catch 

 (96,122). The numbers of each of the other species captured 

 and the percentage of the total catch were as follows : Miis- 

 cina stabulans (Fallen), 3473 (3.61); M. assimilis (Fallen), 

 34 (.03) ; Lucilia sericata (Meigen), 1456 (1.51) ; L. caesar 

 Linnaeus, 103 (.09) ; L. sylvarum (Meigen), 15 (.025) ; Phor- 

 mia terracnovae (Desvoidy), 25 (.03) ; P. regina (Meigen), 244 

 (.25) ; Calltphora, including erythrocephala (Meigen), color- 

 adensis Hough and latifrons Hough, 123 (.13) ; Fannia, in- 

 cluding scalaris (Fabricius), caniciilaris (Linnaeus) and an 

 undetermined species, 2294 (2.38) ; Ophyra leucostoma Wied- 

 emann, 18 (.02) ; undetermined Anthomyidae, 5 (.005) ; 

 Ravinia communis R. Parker, 36 (.04) ; R. peniculata R. Par- 

 ker, 14 (.015) ; Sarcophaga hacmorrhoidalis (Fallen), 5 

 (.005) ; S. coulcyi R. Parker, 7 (.008) ; Bocttcheria cimhicis 

 (Townsend), i (.001). Anacampta latiuscula, 5 (.005) ; Cnlex 

 tarsalis Coquillett, 9 (.01). Species of Borhoridae and of 

 Scatopse were very numerous, but of course no record of them 

 could be secured by means of Hodge traps. 



The above data indicated the great predominance of house 

 flies during the summer months, even under out-door condi- 

 tions. Their comparative abundance may be expected to be 

 even greater under less rural conditions. The abundance of 

 species of Fannia, particularly scalaris, and of the blow flies 

 would likely be less in towns having adequate systems for the 



