BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 11 
with the other climates, the Fort Pierce simulation possessed the most 
nearly ideal meteorological conditions for development of this species. 
Almost year-round reproduction took place, a fourth generation being 
completed late in the winter. 
Climatic conditions that may adversely affect fruit fly development 
or that may be fatal to established infestations, are part of a continu- 
ous study with these chambers. 
Climate limits fruit fly development 
Eleven stations at elevations ranging from sea level to 9,200 feet 
on the islands of Maui and Hawaii, have furnished sufficient data to 
indicate in some measure the limitations imposed by climate on the 
development of the melon fly and the oriental and Mediterranean 
fruit flies. 
Adult fruit flies were able to live for extended periods under cool 
temperatures: sometimes for more than a year. In mainland areas 
where similar conditions prevail during winter periods, the flies should 
be able to survive and later produce progeny when temperatures 
become more favorable. 
The oriental fruit fly showed higher survival in areas with tempera- 
ture peaks high enough to permit some development than it did in 
areas where the temperature held within a narrow range near the 
survival threshold. 
Of the three species of flies 5 the melon fly was able to tolerate greater 
extremes of temperature and relative humidity. It developed at 
lower temperatures than did either the Mediterranean or oriental 
fruit flies. % 
Longevity studies showed that all three flies may survive long 
enough to bridge 2- or 3-month periods when no fruit is available to 
them. After surviving in cool areas for more than a year, melon 
fly females were still able to produce eggs that hatched. 
Traps determine intensity of fruit fly infestations 
Intensity of oriental fruit fly infestations on Maui. Hawaii, and 
Oahu were determined by means of glass traps baited with methyl 
eugenol, citronella or with fermented lures by the Bureau and the 
University of Hawaii. Peaks of infestation again proved to be in- 
variably correlated with periods of greatest abundance of fruit. 
The infestation on Oahu was greatly reduced from the original 
peak infestations. There were also fewer flies on Maui and Hawaii 
as a result of the work of the parasites. Nevertheless substantial in- 
festations in preferred fruits demonstrated that a serious though less 
severe problem persists. 
Foreign parasite introduction program completed in Hawaii 
The introduction of parasites into Hawaii from foreign countries, 
initiated as a cooperative project in 1948, was brought to a close in 
the fall of 1951 with the return to the United States of the last two 
explorers, one from Africa and the other from southeast Asia. During 
1951 nearly 150 shipments containing more than 1 million fruit fly 
puparia were received in Hawaii from East and West Africa, South 
India, Siam, North Borneo. Fiji. Java, Ceylon, and Brazil. From 
