jan. io, 1916 Effect of Cold Storage on Mediterranean Fruit Fly 659 
33° to 35 0 for more than 15 days, and advised that fruit kept within 
this range of temperature for three weeks would be perfectly free from 
living forms. His report indicates that the work was done carefully. 
The work of Wilcox and Hunn (7) in 1914 has shown that such semi- 
tropical host fruits as the star-apple, fig {Ficus spp.), papaya (Carica 
papaya ), mango, and avocado withstand without injury to texture or 
flavor a temperature slightly above 32 0 for from 27 days in the case of 
papaya to two months in the case of the avocado. Such periods at 32 0 
are well above the margin of safety for complete mortality of the larvae 
and eggs of the fruit fly. 
EXPERIMENTAL WORK 
In determining the effect of cold-storage temperatures upon the eggs 
and larvae of the Mediterranean fruit fly, the writers have been fortunate 
in securing the cooperation of an ice company during 1913 and of an 
electric company during 1914 and 1915. At the cold-storage plants of 
these companies there’were to be had all^the facilities found in modem, 
well-regulated cold-storage plants. While an abundance of fruit-fly 
material is to be had in and about Honolulu, the writers have preferred 
in their work to infest in the insectary host fruits known to be previously 
free from attack. As no such fruits can be found in Hawaii under 
natural conditions, apples (Malus spp.) from California were used. These 
fruits were suspended for several hours in jars containing several hundred 
ovipositing fruit flies and then removed and held in the insectary for the 
number of days which experience had shown was necessary for the flies 
within to reach the stages desired for experiment. In this way larger 
amounts of material in definite stages could be used at one time than 
otherwise. While much of the data recorded in Table I was secured 
from fruit flies in apples, a sufficient amount, including observations on 
many thousands of eggs and larvae, has been secured from fruit flies in 
peaches and kamani nuts {Terminalia catappa ), as checks, to prove that 
there is no probability that the nature of the host fruit affects the action 
of temperatures. 
No examination of material to determine the effect of various tem¬ 
peratures was made until the host fruits had been removed from storage 
from 24 to 48 hours. By placing the host fruits within storage the eggs 
and larvae were under normal conditions. On examination the eggs were 
dissected out of the punctures and placed in moist chambers where all 
that hatched might be recorded. Larvae found torpid though normal in 
color on examination within 24 to 48 hours after removal from storage 
invariably failed to resume activity. 
THE EGG 
No eggs hatch in cold storage if held at temperatures below 50° F. 
A temperature of 32 0 proved quickly fatal to eggs. A total of 6,747 
eggs were under observation. No eggs hatched upon removal from 
