42 BULLETIN 491, l\ S. DEPARTMENT OF AGBICULTUBE. 



the puparia, when the average mean temperature ranged from 78.7° 

 to 79.4 F. 



During the winter months in the Kona district of Hawaii, where 

 the lowest moan temperatures at Kealakekua were about 68° F., 

 with a daily temperature ranging between 58° and 78° F., the dura- 

 tion of the pupal stage is considerably lengthened. Thus 7, 6, and 

 1 pupae yielded adults 20, 21, and 22 days, respectively, after the 

 formation of the puparium. From 175 puparia formed between the 

 1st and 3d of February, 2, 7, 151, 12, and 3 adults emerged on Feb- 

 ruary 20, 21, 22, 23, and 24, respectively. At Kaawaloa, a hot 

 sheltered spot at sea level, but "within 2 miles of the station at Keala- 

 kekua. where the temperature ranged from 63° to 89° F., 126 pupae 

 formed on February 23 produced 5, 107, and 2 adults on March 5, 

 C and 7, respectively, or in from 10 to 12 days after the formation 

 of the puparium. 



It w T as found by carrying pupa; to higher altitudes than those at 

 which the host fruits of the melon fly occur in Hawaii that the dura- 

 tion of the pupal stage might be considerably lengthened. Thus 143 

 puparia just formed at Kealakekua on January 26, 1915, were taken 

 the same day to Puulehua at about 5,000 feet elevation, where the 

 average mean temperature from January 14 to March 19 was about 

 51.6° F. and where the daily range in temperature showed a varia- 

 tion from a minimum of 31° F. to a maximum of 72° F. From 

 these pupae, removed to Kealakekua on March 25, 3 adults emerged 

 on March 26. Therefore at this temperature the duration of the 

 pupal stage may be at least 59 days. 



One hundred and twenty-four pupa? formed between February 19 

 and 21, 1915, and 76 pupa? formed on February 22 and 23 at 

 Kealakekua were taken on February 24 to the summit of Hualalai, 

 8,275 feet elevation, where the average mean temperature during 

 February and March was about 46.3° F. and the daily range from 

 a minimum of 27° F. to a maximum of 73° F. These pupae were 

 removed to Kealakekua on March 26 and on March 31, 6 and 1 adult 

 flies, respectively, emerged. For these 7 pupae the duration of the 

 pupal stage extended from 36 to 40 days. 



It is the opinion of the writers that had it been possible to con- 

 tinue experimental work at Puulehua and on Hualalai, the duration 

 of the pupal stage might have been still further extended, but not 

 by very many days. 



