87 



Although the sudden change from summer temperature to freez- 

 ing was quite abnormal, the difference in results from the three lots 

 is very instructive with respect to the pupae in loose earth and those 

 in the cells. Not a single pupa survived freezing in a broken cell, 

 while a number successfull}^ withstood it when resting in their cells. 



The effects of this cooling did not disappear at all on the pupje which 

 had failed to emerge within a month after removal from cold storage, 

 and they passed into winter hibernation. 



Later in the month the experiment was practical!}^ repeated with a 

 box containing about thirty pupae, half of them in normall}' con- 

 structed cells and the others buried under an inch of moist soil. The 

 box was first cooled at a temperature of 34^ for twent3^-f our hours and 

 then frozen at 27^ for three days. No moths appeared until Decem- 

 ber 10, when a male moth emerged. Four da3^s later the pupse were 

 examined and it was found that three live ones still remained in their 

 pupal cells, while all those buried in loose earth had been killed. 



HEAT. 



The effect of hot sunshine on pupae was tried during August, 1903, 

 at Calvert, Tex. Three pup^e, two days old, were placed on the hot 

 soil at noon where the sun shone on them and left for a period of ten 

 minutes. On removal to normal surroundings at a subsequent exam- 

 ination all were found to be dead, due, no doubt, to the heat. 



Experiments show, however, that pupae can withstand heat much 

 more readil}^ under conditions of great humidity. Twenty healthy 

 pupa3 were covered with about half an inch of loose damp soil and left 

 where the sun could strike them. During the next five days two 

 good rains fell, after which the pupje were examined. Sixteen were 

 alive, one was parasitized, and two were dead. On another occasion 

 four pupae were placed in artificial cells in the laborator}^ garden where 

 the sun could strike them and covered with a bell jar. In spite of the 

 humid atmosphere and heat three perfect moths emerged. 



The moisture content of the soil does not seem to influence the 

 length of the pupal stage. Of two boxes, each containing twenty 

 pupae in normal cells, one was watered and kept continually damp, 

 while the other was left to dr3\ From the dry box there emerged 

 'thirteen moths, and from the wetted one, eleven, the pupal stage being 

 nineteen days in each case. However this may be, it has been noticed 

 that lots of pupae which have been under dr}^ conditions until about 

 ready to emerge will often do so more quickly if the ground be 

 wetted. 



