304 ENTOMOLOGICAL NEWS [Julv, '13 



The question is constantly asked : What becomes of the flies 

 during the winter? Most of them die; the remainder hiber- 

 nate." 



Sanitarians have accepted the hibernation theory and rec- 

 ommend killing all the flies seen in the early spring, which 

 they say are all hibernating females, about to oviposit. In 

 this way they hope to cut ofif the egg supply in its incipiency. 



Observations made this past spring appear to show that the 

 house-fly lives through the winter in the pupal stage. If 

 this be correct, it seems reasonable to suppose that it is the 

 only w^ay in which the insect lives through the winter, on the 

 theory that insects belonging to this order only pass through 

 the winter in a given stage and never in two stages. The 

 observations were made in the entomological rooms of the 

 Academy of Natural Sciences of Philadelphia. No flies were 

 observed in the rooms during the past winter, but as soon as 

 the first warm days of early spring arrived the windows were 

 opened and flies came in. Some of these were caught on 

 March 13th of this year. They were all fr;esh specimens, 

 even teneral in character except in color. The ptilinum w-as 

 not completely retracted and it was evident that they had 

 just emerged. The colors were bright and the wings perfect 

 and not frayed in any way, and there was no sign of dust, dirt 

 or decay on them. All in all it was quite evident that they 

 had recently emerged. Both sexes were represented. Until 

 disproved, I will answer the question at the head of this ar- 

 tice as follows : House-flies pass the winter in the pupal stage 

 and in no other way. 



Charts of Food Plants of Lepidoptera. 



Miss Ximcna McGlashan. from her Ruttertl)- Farm at Truckee, Cali- 

 fornia, has sent out several lists of food-plants of North American 

 Butterflies and Moths, dated January, March, April and May. 1913. re- 

 spectively. As summaries of information they are very useful, but it 

 has been suggested that the size, especially of the larger "charts." is 

 inconvenient and cumbersome and that ordinary book or pamphlet 

 form would be more agreeable. Miss McGlashan asks the aid of all 

 interested in the compilation of a complete list. 



