THE MELON ELY IN HAWAII. 43 



Table VII. — Duration of the pupal stage of the melon fly at Honolulu. 



Date of pupation. 



Date of emergence. 



Number 



Number 



Average 



of adults 



of days 



mean 



emerg- 



in pupal 



tempera- 



ing. 



stage. 



ture. 







°F. 



5 



8 



78.7 



25 



9 



78.9 



1 



11 



78.9 



60 



8 



79.3 



1 



8.5 



79.3 



27 



9 



79.2 



1 



7 



79.3 



17 



8 



79.4 



25 



9 



79.4 



26 



9 



79.2 



37 



10 



79.2 



355 



9 



79.4 



33 



10 



79.3 



300 



9 



79.4 



15 



10 



79.3 



45 



12 



71.6 



192 



13 



71.6 



38 



12 



71.6 



228 



13 



71.6 



Average 



mean 

 relative 

 humidity 



Aug. 14, a. m. 



Do 



Do 



Aug. 17, a.m. 



Do 



Do 



Aug. 18, a. m. 



Do 



Do 



Sept. 17, a. m. 



Do 



Sept. 20, a. m. 



Do 



Sept. 19, a. m. 



Do 



Feb. 3, a.m.. 



Do 



Feb. 4, a. m.. 



Do 



Aug. 22, a.m. 

 Aug. 23, a. m. 

 Aug. 25, a. m. 

 ....do 



Aug. 25, p. m. 

 Aug. 26, a. m. 

 Aug. 25, a. m. 

 Aug. 26, a. m. 

 Aug. 27, a. m. 

 Sept. 26, a. m. 

 Sept. 27, a. m. 

 Sept. 29, a. m. 

 Sept. 30, a. m. 

 Sept. 28, a. m. 

 Sept. 29, a. m. 

 Feb. 15, a. m. 

 Feb. 16, a.m. 



do 



Feb. 17, a. m. 



P<r 



cent. 

 72.5 

 71.6 

 70.8 

 69.4 

 68.7 

 68.7 

 67.8 

 67.2 

 66.6 

 72.1 

 70.8 

 69.4 

 69 

 70.1 

 69.5 

 74 



74.2 

 74 

 74.2 



LENGTH OF LIFE CYCLE. 



During the warmest Hawaiian weather, when the mean tempera- 

 ture averages about 79.5° F., the egg, larval, and pupal stages may be 

 passed in as few as 12 or as many as 28J days, according to the indi- 

 vidual and its host. The complete life cycle is subject to 'great 

 variation, according to the longevity of the adult. As one adult has 

 been kept alive for 431 days it is evident that the complete life cycle 

 from the deposition of egg to the death of the adult may be 443 to 

 459 days when the immature stages are passed during the warmer 

 portion of the year. At an average mean temperature of about 68° 

 F., which is the coolest mean temperature found by the writers in 

 Hawaii, where host fruits are available for the fly and for observa- 

 tion, the egg, larval, and pupal stages are passed in from 40 to 45 

 days. It is difficult to state just what variation there may be in the 

 length of the life cycle in still cooler climates, but it is capable of 

 being rather great in the opinion of the writers. The pupal stage 

 in Hawaii has been lengthened from 6 clays at a mean of 79° F. to 

 59 days at a mean out-of-door temperature of about 5.6° F. In 

 like manner the egg stage has been lengthened from 26 hours at 79° 

 F. to 11 days at 49° to 52° F. in storage, the third larval stage from 

 two days at 79° F. to at least 23 days at 56° to 62° F., and the first 

 larval stage from 20 hours at 79° F. to 27 days at 56° to 62° F. 

 The writers believe that with certain combinations of host fruits 

 and temperatures the immature stage may require 3J to 4 months, 

 or a sufficiently long time to carry the pest over any cool period 

 likely to be experienced by the melon fly in any habitat where it 

 can establish itself, 



