eS 
~13- 
wise, the percentage of larvae pupating decreases as the exposure in- 
creases, and the percentage of pupae emerging as adults decreases as 
the time of exposure increases. Thus, many of the larvae subjected to 
the heat treatment are able to emerge from the fruits anc pupate, but are 
weakened by the heat to such a degree that the pupae die before the ad~ 
ults emerge. In another experiment employing naturally infested sour 
oranges consisting of 770 larvae, complete mortality was obtained be- 
tween 43 and 53 hours when heated at 109.87° F. From data obtained 
to date, the temperature and time of exposure employed in Florida are suf- 
ficient to give complete control in Hawaiian naturally infested fruits." 
Experiments with low temperatures are described as follows: 
"Seven lots of sour oranges held at an average temperature of 28° F. 
gave complete mortality after an exposure of 120 hours A total of 
S82 larvae were employed in these tests. A number of the larvae emerg~ 
ing at the end of 48, 72, and 96 hours did not produce normal pupae. 
eeveral of the larvae retained their normal shape but a chitinous 
covering formed about the larvae that had the appearance and texture 
of pupa case. In no case were the deformed pupae able to produce normal 
adulis. In kamani nuts, one larva emerged and pupated in the lot ex- 
posed for 144 hours at 28° F. The pupa died before the adult emerged. 
This series of tests included 6,335 larvae. * * * The data obtained to 
date show that the minimum exnosure of infested fruits to a temperature 
of 28° F. is 144 hours (6 days)." 
Penetration of soil by adults of the dark fruit fly.--James Ze~- 
jek, Panzma Canal Zone, reports that "fifty larvae of Anastrepha ser— 
pentina Wied. were placed on top of a tube of soil 3 inches in diameter 
and 26 inches high. After 4 days the tube was inverted. Only one 
adult found its way cut 16 days afier pupation. When the tube of earth 
was carefully examined, it was found that the larvae pupated about 
4 inches from the surface, so that the adults had to travel through 
about 23 inches of earth. We found 45 dead adults half way up, that 
is, 13 inckes from the top. Three puparia were dead and in cne instance 
the adult died before getting entirely out of the puparium. It is evi- 
dent that 23 inches of soil is too much for the adults. We have many 
records of exact depth to which larvae descend to pupate. Usually it 
is within a few inches of the top." 
Gains in Trichogramma host produgtion.--Herbert Spencer and Luther 
Brown, engaced in investigations of parasites of pecan insects at Albany, 
Ga., report that "During March, 321,100 Angovumois grain moths were col- 
tected in one of the incubator rooms, and from these moths 4,512,000 eggs 
vere cbtained. Three million eight hundred and fifty thousand were placed 
in a second incubator room filled with trays of corn to start infesta- 
tion, and increase of the Trichogramma consumed the remainder. This March 
preduction of moths and eggs is far ahead of that of March, 1951, when 
cnly 30,800 moths were collected, and only 154,000 eggs were cbtained. 
* * * No mites of any species are present in the incubator rooms, an 
