68. 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



will prevent destruction by cold, and yet with temperatures low enough 

 to prevent activity, and in this way pass the winter. We are inclined 

 to the opinion that the chances of such conditions being found are small 

 and that, although some adults may in this way hibernate, the species 

 is dependent largely on those individuals which pass the winter in the 

 immature stages, or those which continue to breed during the winter. 

 Under Texas conditions we are convinced that this opinion is correct. 



To determine the ability of the adults to pass the winter at Dallas, 

 Texas, a cage of screen about ten feet square by six feet high was fitted 

 up with stacks of boards, burlap, paper, etc., for hibernating quarters. 

 Over six hundred adults, about sixty per cent of which were males, 

 were introduced into the cage between November 9 and November 

 19, 1913. These were mainly newly-emerged adults bred from manure. 

 Food, consisting of bananas, milk, and water, was supplied. Unfor- 

 tunatety the fungus, Empusce musccE,wsiS unusually abundant during 

 this autumn and the flies in this cage died in great numbers. Probably 

 the majority of them died of this disease. No flies were seen in the 

 cage after November 28, although frequent observations were made 

 during the winter, and in spring a thorough search failed to reveal any 

 living flies in the shelter provided. 



At Uvalde, Texas, a similar experiment was conducted, four hundred 

 adult flies being introduced into a large screened cage between Decem- 

 ber 18, 1913, and January 3, 1914. The flies were supplied with plenty 

 of protection and food. They were observed to seek protection in the 

 rubbish to some extent when the weather became cool. On warm days 

 they resumed activity, feeding, and copulating in some cases. 



On January 20, sixty-four adults were found benumbed by cold 

 weather outside of the hibernation material. None of these revived. 

 On January 27, a number were seen to be active in the cage during the 

 warm part of the day. The last adults (two) observed in the cage 

 were seen on January 28. No further activity was noted during the 

 winter and early spring, and no living flies were found on final exam- 

 ination of the hibernation material. 



To test the possibility of adults hibernating in buildings where arti- 

 ficial heat is supplied, several hundred flies, bred out in a cage in a 

 small room in the laboratory at Dallas (a great number were also free 

 in the room), were supplied with food, and fire maintained when the 

 weather was cold. The adults began emerging December 30, 1913, 

 from manure infested with larvae put in the cage December 12. Emer- 

 gence was allowed to continue for some weeks. The temperature fell 

 to 36° F. on one occasion and once got up to 110° F. for a short time, 

 but usually ran between 50° F. and 75° F. On January 21 larvae were 

 found which had developed from eggs probably deposited about Jan- 



