254 



Journal of Agricultural Research 



Vol. VI, No. 7 



Temperatures of from 33° to 34° F. — Only 3 out of 207 pupae held 

 at 33° to 34° F. for 4 days and at 43° to 45° F. for 8 additional days 

 yielded adults. 



Temperatures of from 33° to 36° F., averaging 34°. — A total of 

 over 27,097 pupae were used in experiments to determine the effect of a 

 temperature averaging about 34° F. but varying between 33° and 36° F. 

 Only I seven-day-old pupa out of 228 of like age or 1,239 of all ages 

 refrigerated for 16 days yielded an adult; 1,228, 1,164, i>694, and 1,931 

 refrigerated for 18, 20, 22, and 25 days were dead on removal from 

 storage. Only 3 out of 272 seven-day-old pupae, or 1,472 pupae of all 

 ages, produced adults after refrigeration for 15 days, while only 8 out 

 of 210 eight-day-old pupae and 3 out of 220 seven-day-old pupae, or but 

 1 1 out of 1 ,630 pupae of all ages from one to eight days old when placed 

 in storage, produced adults after refrigeration for 14 days. After refrig- 

 eration for 12 days, 12 eight-day-old pupae, 11 seven-day -old pupae, 2 

 six-day-old pupae, and 8 one-day-old pupae out of a total of 1,580 pupae 

 of all ages produced adults. From i to 30 adults emerged from lots of 

 all ages of pupae, totaling 1,519 forms, except from 126 five-day-old 

 pupae, after refrigeration for 11 days, but from i to 3 adults emerged 

 from all lots yielding adults, except from the seven-day-old pupae, which 

 yielded 30 adults from a total of 265 pupae. 



Refrigeration of i ,685 pupae of all ages for 9 days did not prove totally 

 fatal to any age. Thus 85 out of 340 eight-day-old pupae, and 88 out 

 of 390 seven-day-old pupae produced adults as compared with 3 four- 

 day-old pupae, 7 three-day-old pupae, and 2 one-day-old pupae out of a 

 total of 475 pupae. 



Some adults emerged from lots of pupae representing all ages on removal 

 from storage after 2, 3, 4, 5, 6, 7, and 8 days of refrigeration. On these 

 days an average of about 1,479 pupae were removed from storage. The 

 number of pupae surviving is indicated by the data in Table II. 



Table II. — Effect upon pupcB of the Mediterranean fruit fly of refrigeration for from i to 8 



days at jj° to 36° F. 



Age of pupae on entering storage. 



Number of pupse yielding adults after removal to normal 

 temperature after refrigeration for — 



2 days. 3 days. 4 days, s days. 6 days. 7 days. 8 days 



1 day. 



2 days 



3 days 



4 days 



5 days 



6 days 



7 days 



8 days 



87 

 41 

 49 

 27 

 12 

 10 

 190 

 129 



59 

 12 

 76 



47 

 21 



15 

 405 

 153 



56 

 25 

 44 

 26 



14 



17 



228 



434 



59 

 6 



II 



10 



10 



221 



146 



16 

 8 



12 



4 

 10 



5 

 188 

 216 



15 

 2 



14 



5 



229 

 150 



9 

 6 

 6 



3 

 4 

 2 



98 

 91 



The data in Table II are introduced to prove that refrigeration for from 

 I to 8 days at this temperature is not fatal, and can not be depended 



