286 The Ohio Journal of Science [Vol. XVII, No. 8, 



and but 30 days (December 16, 1914-February 2, 1915) extreme 

 temperature 13°-62°, mean 30°, in the insectary. Eggs were 

 not deposited in the insectary until April 20, while in the stable 

 they were noted on May 6th. These trials therefore show that 

 the adults died under modified winter conditions after a short 

 exposure. 



These experimental results colaborate those obtained by 

 Dr. F. C. Bishopp (1915), "Notes on Certain Points of Economic 

 Importance in the Biology of the House-fly, " who concludes 

 that, "flies which are not kept cold enough to become inactive 

 will either deposit if the temperature is sufficiently high or die 

 comparatively soon." The climatical conditions in Texas 

 are different from those in Maryland and Ohio. This point of 

 varience from Dr. F. C. Bishopp's conditions was well expressed 

 in his remarks that ' ' oviposition was observed to occur on warm 

 days in midwinter at Dallas, Texas, January 14, and at Valde, 

 Texas, on February 5, 1914. Depositions may be expected at 

 these latitudes on mild bright days in winter, especially if 

 these are preceded by a few days of mild weather. During 

 cool weather adults seem to choose places for deposition where 

 the sun is bright and the wind is cut off." 



At Columbus, Ohio, several student boarding houses and 

 private houses were examined from roof to basement once a 

 w^eek throughout the winter of 1916-17. A search for flies 

 was also made in the vicinity of the garbage cans of these 

 stations. On December 17, 1916, a total of 7 males and 5 

 females of Musca domestica L. was collected in the kitchen. 

 Then no adults were observed nor collected until a comparatively 

 warm period about January 10, which brought 1 male and 2 

 females to the dining room of a private home and on January 

 28, two males were swept in slow flight from a gas pipe near 

 the ceiling of a kitchen. At the latter station (a boarding club) 

 no extra precautions were taken to screen food products. 

 As a check, however, upon such careless conditions, a private 

 home where every possible precaution was taken, such as 

 screening and covering fly-attractive substances, was examined 

 weekly. The latter station revealed two female Musca domestica 

 on November 5, 1916, as the last collected up to the present 

 writing, April 5th. Musca domestica was observed in flight in 

 a restaurant, March 10, 1916. Therefore from January 28th to 

 March 10th no adult houseflies were observed in dwelling houses. 



