264 ENTOMOLOGICAL NEWS. [June, '15 



On February the I5th of the present year, the windows 

 of the Entomological Department of the Academy of Natural 

 Sciences of Philadelphia were opened on account of the mild 

 weather, and house-flies (Mnsca domestica) came in. Pre- 

 vious to this date no flies were seen in the rooms. A local 

 newspaper contained the following item : "Philadelphia ex- 

 perienced yesterday one of the warmest February i5ths in the 

 history of the weather bureau. At 1.30 o'clock in the afternoon 

 the thermometer touched 67 degrees F., which was the highest 

 reached by the mercury on February I5th in forty years. As 

 a result of the unusually mild weather conditions many men 

 cast aside their overcoats, while hundreds of women appeared 

 on the streets without furs." No special effort was made to 

 obtain house-flies and only those that came conveniently within 

 reach were caught. Some were netted and killed in a cyanide 

 bottle and some were "swatted." Mr. E. T. Cresson, Jr., the 

 well-known student of the Diptera, has given me the following 

 report on the Musca domestica taken early this season. 



Two females killed February isth at the Academy. Chitin soft, and 

 in drying the face and abdomen of the fly became very much shrunken. 

 The clean pollen and undamaged bristles indicated recent emergence 

 from the pupa. 



One female February I7th showed same condition, but less shrunken. 



One male February 23rd. Very much shrunken. This specimen 

 was mutilated from the method of killing, being swatted. 



One female Philadelphia, Pa., April 6th. Well developed and clean. 



It is significant that no hibernated specimens were seen. 

 Also that a freshly-emerged male was taken. It is, therefore, 

 a fact that house-flies of both sexes emerge from pupae in the 

 late winter or early spring and that these flies are capable of 

 producing the heavy summer broods. These facts show how 

 little we really knew about this very common insect in relation 

 to hibernation, and there is still much to be known and put on 

 a firm basis. It is hardly worth while to speculate in regard 

 to the living through of some females capable of oviposition 

 in the spring. This awaits exact observation. It will also be 

 of value to look for living pupae in the winter and early 

 spring. 



