FLIES THAT FREQUENT HOUSES 



39 



over, the thorax of the cluster-fly bears many short, 

 golden hairs. The thorax is of a uniform coloration and 

 lacks the light and dark lines on the thorax of the house- 

 fly. The abdomen is grayish but inclined to be iridescent, 

 and thickly set with hairs, especially at the posterior end 

 and along the sides. 



Its habits. — Normally the cluster-fly lives out-of-doors, 

 frequenting the flowers and fruits of plants. In the 

 autumn, however, it enters dwelling-houses in search of 

 snug retreats in which to pass 

 the winter. It gathers in clus- 

 ters in the corners of unused, 

 darkened rooms, under clothing 

 in closets, beneath curtains at 

 windows, and in other nooks. 

 A correspondent writes, "Can 

 you give me information con- 

 cerning the house-fly which in 

 late August and September gets 

 into unused rooms where there 

 is no food or odor and bunches 



in the angles of the wall and behind pictures and fur- 

 niture ? They do not fly much but crawl about in a 

 lazy manner. Screens and every device which works 

 perfectly in excluding the ordinary fly are useless in 

 keeping these out." This letter describes the habits of 

 the cluster-fly admirably. 



W. H. Dall quotes from a letter of a relative living at 

 Geneva, New York, who had been much troubled with 

 these flies. Evidently the flies had been troublesome in 

 the neighborhood, for the letter says, "people soon learned 

 to look everywhere ; in beds, in pillow-slips, under table 



Fig. 15. — The cluster-fly. 

 (X2L) 



