MEDITERRANEAN FRUIT FLY IN HAWAII. 109 



historical facts dealing with the use of such temperatures, one should 

 consult the two articles to which reference has been made. Fruits of 

 almost any variety commonly placed in cold storage are held at 

 temperatures varying from 32° to 45° F., with preference shown to a 

 range of 32° to 36° F. By way of general summary of many experi- 

 ments, including observations upon over 26,000 eggs, 60,000 larvae, 

 and 173,000 pupse to determine the effect of such temperatures as 32°, 

 32° to 33°, 33° to 34°, 34° to 36°, 36°, 36° to 40°, 38° to 40°, and 40° 

 to 45°, it may be said that no stage of the Mediterranean fruit fly can 

 survive refrigeration for seven weeks at 40° to 45° F. ; for three weeks 

 at 33° to 40° F., or for two weeks at 32° to 33° F. 



EFFECT OF FREEZING TEMPERATURES UPON THE EGG, LARVA, AND PUPA. 



The only freezing temperatures available in Hawaii for experi- 

 mental work with eggs, larvae, and pupae were those found in cold- 

 storage plants maintaining rooms for the refrigeration of fish and 

 meat. The temperature of these rooms ranged between 21 ° and 30° F. 

 though averaging close to 26° F. Out-of-door freezing tempera- 

 tures have been experienced by the writers on the Island of Hawaii 

 at an elevation of over 8,000 feet, but lasted only for a few hours 

 at a time and occurred on mountain slopes not easily accessible. 



THE EGG. 



Apples in which fruit-fly eggs had been deposited on November 3, 1914, were 

 placed in cold storage at a temperature varying from 24° to 30° F. Fruit was re- 

 moved daily for 10 consecutive days and observations made on a total of 5,434 eggs 

 contained within them. No eggs survived more than 7 days of refrigeration at this 

 temperature. Of 507 eggs subjected to 25° F. for one day 414 hatched on removal to 

 normal temperature; 275 of 308 eggs subjected to 24° to 25° F. for 2 days hatched 

 after removal; 588 of 741 eggs hatched on removal after refrigeration for 3 days at 

 24° to 26° F.; 430 of 748, 65 of 384, 7 of 534, and 1 of 255 eggs hatched on removal after 

 refrigeration at 24° to 30° F. for 4, 5, 6, and 7 days, respectively. All of 606, 624, and 

 727 eggs removed to normal temperature after 8, 9, and 9 days of similar refrigeration 

 were dead. 



In a second experiment carried out during July, 1913, peaches containing eggs 

 were picked promiscuously in the field, and placed in storage at 26° to 30° F. The 

 results were similar to those mentioned above, as 42 of 178, 7 of 10, and 20 of 145 eggs 

 hatched on removal, after refrigeration fori, 2, and 6 days, respectively; 57, 148,82, 

 134, and 14 eggs refrigerated for 7, 9, 10, 11, and 12 days were dead on removal from 

 storage. 



THE LARVA. 



First-instar larvae,. — A total of 2,116 first-instar larvse were placed in cold storage at 

 21° to 28° F. None survived more than 5 days of refrigeration, and the following 

 observations were recorded: 62 of 248 larvge in refrigeration for 5 days were found 

 living on examination after removal to normal temperature; 297 of 340 survived one 

 day of refrigeration at 22° to 23° F.; 239 of 275 survived two days of refrigeration at 

 21° to 23° F.; 110 of 243, and 44 of 240 survived refrigeration at 21° to 28° F. for 3 and 

 4 days, respectively; 264, 132, 213, and 141 larvae refrigerated for 6, 7, 8, and 9 days, 

 respectively, were dead on removal from storage. 



