534 JOURNAI, OF ECONOMIC ENTOMOLOGY [Vol. 9 



merits, makes it impossible to determine the maximum length of the 

 larval stages. To have examined the infestation would have caused 

 abnormal conditions. However, in Breeding No. 66, in which infested 

 manure was placed in a cage and subjected to two inundations, larvse 

 were present from November 26, 1913, to March 21, 1914, a period of 

 at least 115 days. In this experiment adults emerged from the over 

 wintering material, and has been reported in a previous paper (1.). 

 In the experiments with larvae which produced no adults there was no 

 soil into which they could migrate to a depth which would be protec- 

 tive to their pupae. 



Pup^ During the Winter 



Confining our attention to the winter pupal periods we find that 

 where pupse were in manure piles in which heat was generated, as in 

 Breeding No. 99, emergence continued until all viable pupse produced 

 adults. In this experiment 85 adults were observed to emerge when 

 the maximum for the twelve hours of emergence was 55° F. and the 

 minimum 43° F. These were the actual temperatures of the media, 

 which consisted of cow manure and some straw. At other tempera- 

 tures above these emergence was most frequently observed. Only 

 when pupse were kept at these or warmer temperatures did they pro- 

 duce adults, and these emerged in a comparatively short time. The 

 inviability of pupse remaining unemerged in Breeding Nos. 65, 100, 

 99, 62 and 56, was determined by warming them during the spring. 

 In Breeding No. 56, the emergence ceased when the box containing 

 pupse was removed from the manure pile, and none emerged thereafter. 

 In Breeding No. 62, pupse were produced by larvse migrating into an 

 old burlap sack which was on the bottom of the tin compartment, but 

 on account of low temperatures none emerged. 



Numerous winter and spring collections of pupse from garbage and 

 old manure piles in various outdoor locations, but which were taken 

 near the surface of the soil or in the media, failed to produce adults 

 when subjected to favorable conditions. It is evident that pupse in 

 such conditions either receive enough heat to produce adults during 

 mid-winter or die from temperatures too low to permit emergence. 

 However, pupal periods have been observed to extend for 26 days or 

 longer, and it is reasonable to expect long periods from pupse formed 

 from migratory larvae which penetrate deep enough for protection from 

 excessive cold or warmth. It is evident from the experiment de- 

 scribed below that larval migration is a great factor in placing pupae at 

 a favorable depth in the soil. 



