2 BULLETIN 161, U. S. DEPARTMENT OF AGRICULTURB. 



EGG, LARVA, AND PUPA. 



Col. W. K. Winter, in his bulletin entitled "The Fruit Fly," pub- 

 lished by the Bermuda Department of Agriculture in 1913, 1 gives the 

 only data secured in Bermuda on this pest up to that date. He 

 states that he has found that to pass through the egg, larval, and 

 pupal stages the fly requires from 17 days, during the heat of August, 

 when the monthly mean temperature averages about 81° F., to 6 

 weeks in winter, when the mean temperature averages about 63.2° F. 



With the assistance of Mr. E. J. Wortley, Director of Agriculture 

 of the Bermuda Department of Agriculture, the writer found that the 

 pupal stage alone in Bermuda, when the daily mean temperatures 

 ranged between 62.5° and about 64.8° F., might be lengthened to 

 about 31 days under normal conditions. 



Back and Pemberton have found that a temperature varying from 

 58° to 62° F. increases pupal life to from 29 to 31 days. They have 

 likewise found that while eggs hatch in from 2 to 3 days in Hawaii 

 at a mean temperature of about 79° F., hatching may be delayed 

 until 6 days after deposition when the mean temperature drops to 

 about 71° F., or until 7 to 14 days when the temperature ranges 

 from 54° to 57° F. It has also been found in Hawaii that while the 

 larval stage may require a minimum of 5 to 6 days at a mean tempera- 

 ture averaging about 79° F., it requires from 36 to 53 days in apples 

 at temperatures ranging from 56° to 57° F. 



These data are given to substantiate the belief of the writer that 

 the duration of life from the egg to the adult in Bermuda where the 

 winter mean averages about 63° F. is somewhat over two months, and 

 may even be three months under unfavorable circumstances. 



THE ADULT. 



In the Hawaiian Islands, where the summers are somewhat cooler 

 and the winters slightly warmer than in Bermuda, adult flies have 

 been kept alive over five months. While the majority do not live 

 this long, the belief has been expressed that a few flies may live to be 

 over six months of age, especially during such cool weather as ob- 

 tains in Bermuda during the winter. Both sexes are sexually im- 

 mature when they emerge from the pupa. At temperatures varying 

 from 76° to 78° F., the sexes mate when 5 to 8 days old, though not 

 until 2 weeks old at 61° to 64° F. One prolific female deposited on 

 an average of about 4.5 eggs per day during the first 18 weeks of 

 her life, and had not then reached her egg-laying capacity. As 

 many as 25 eggs have been laid by a single female in one day. Female 

 flies do not lay a large number of eggs at one time and then die, as 

 many believe, but lay quite regularly a few eggs nearly every day 

 throughout fife. 



> Winter, W. R. The fruit fly. Bermuda, 1913. 14 p. (Bermuda Dept. Agr., E. J. Wortley, director.) 



