354 ENTOMOLOGY 



peratures, in which the weevil dies in 1 5 minutes to i second, according 

 to the temperature, 140 being the maximum fatal temperature. 



In the descending scale of temperature, there is a range between 56 f 

 to 24 within which the beetles hibernate. Below 24 is the lower range 

 of fatal temperatures, with 7 as the minimum fatal temperature. As 

 the limits of these ranges vary with moisture and other factors, these 

 ranges, as given by Hunter and Pierce (1912) are necessarily approxima- 

 tions; but they serve to illustrate the fact that such ranges exist, and 

 are accurate for the particular conditions under which they were made, s 



It may be mentioned that Hunter and Pierce found that the winter 

 cold is, on the average, almost twice as effective as summer heat in | 

 killing the beetle; which has several times been greatly reduced in 

 numbers by early freezes in the South. 



High temperatures are more favorable to the activities of insects 

 than to those of human beings. The temperature range of activity 

 varies with different species. 



The effect of temperature upon the locomotor activity of the boll 

 weevil was tested by Dr. A. W. Morrill, who found that as thd tem- 

 perature was gradually raised the activity of the weevils increased up 

 to 105 F. At 95 the beetles were very active; at 86 they began to 

 lose their activity; and at 37 all movement ceased. Out of doors, 

 weevil activity began and ceased at about 75; feeding continuing at :i 

 lower temperatures than oviposition. 



The number of daily feeding punctures of the weevil was found to be 

 greatest at about 80 F., as was also the number of eggs laid. (Hunter 

 and Hinds.) 



The curve representing the average number of eggs deposited daily 

 by the alfalfa weevil, Phytonomus posticus, follows the curve of the mean 

 daily temperature in all its major fluctuations, the highest record 

 (twenty-six eggs) occurring on the day (May 18) with the highest mean 

 temperature (72 F.) of any day previous to June 6. (T. H. Parks.) 



By stimulating the activities of insects, high temperatures diminish i 

 the longevity. Thus a worker honey bee that hibernates may live for 

 six or seven months, but an active worker in summer lives only five or 

 six weeks. 



Other things being equal, the longevity of insects in general is 

 lengthened by a decrease in temperature and shortened by an increase 

 (when these temperatures are between about 42 and 72 F.) ; the differ- 

 ence in longevity of a species at different temperatures corresponding 

 roughly to the difference in temperature. (J. P. Baumberger.) 



