May IS. 1916 Cold Storage and Pupce of Mediterranean Fruit Fly 253 



tuation. The temperatures 49° to 51°, 52° to 56°, and 54° to 57° were not 

 obtainable in the Honolulu cold-storage plants, hence in experiments at 

 these temperatures ordinary refrigerators were used, as indicated. Usu- 

 ally pupae of all ages from i to 9 or 10 days were obtained for each experi- 

 ment, in order that varying effects upon pupae in different stages of 

 development might be noted. The pupae were sifted from sand beneath 

 host fruits and placed in storage either in bulk of several thousand in 

 large jars or, as was more usual, in smaller lots of from one to several 

 hundreds in vials about i inch in diameter and stoppered with cotton. 

 Pupae were not placed in or on damp sand or soil, as early experimental 

 work indicated no advantage from this treatment when pupae are sub- 

 jected to cold-storage temperatures. The humidity of the storage rooms 

 varied between 80° and 91°. After refrigeration the pupae were removed 

 to the laboratory, where they were daily observed for emergence records. 



The term "pupa" is used to designate that period in the life history 

 between the formation of the puparium by the larva and the emergence 

 of the adult. 



Temperature, 32° F. — Of the 13,900 pupae of all ages subjected to 

 refrigeration at a temperature varying less than half a degree either 

 above or below 32° F. during the experiment, none survived more than 

 10 days. In Table I are recorded the results of observations on pupae 

 refrigerated from 2 to 10 days. 



Table I. — Effect upon Mediterranean fruit-fly pupa of refrigeration at J2° F. for from 



2 to 10 days 



Age of pupse on entering 

 storage 



1 day. 



2 days 



3 days 



4 days 



5 days 



6 days 



7 days 



8 days 



9 days 



Number of pupae yielding adults after removal to normal temperature after 

 refrigeration for — 



2 days. 3 days. 4 days. 5 days. 6 days. 7 days. 8 days. 9 days. 10 days 



15 

 20 



32 

 18 

 28 

 29 

 48 

 52 

 51 



6 

 28 

 21 



17 

 18 



27 

 33 

 39 

 33 



3 

 20 



Each lot removed after from 2 to 8 days of refrigeration contained 100 

 pupae; hence, the number of pupae yielding adults represents also the 

 percentage of survival. Very few pupae survived refrigeration at this 

 temperature for longer than one week. Thus only 3 three-day-old pupae 

 out of 900 pupae of all ages survived refrigeration for 8 days, and only i 

 three-day-old pupa survived refrigeration for 9 days. While the data 

 in Table I do not show it, the one surviving 9 days of refrigeration was 

 one out of 300 of like age, and one out of i ,900 of all ages. Not one of 

 4,500 pupae refrigerated for 10 days survived. 



