MEDITERRANEAN ERUIT FLY IN HAWAII. 67 



hatched normally. Records on file show that the eggs deposited 

 by 12 other females isolated after mating on September 8 hatched 

 normally. 



SEXUAL SMELL. 



The writers have found that the males of the Mediterranean fruit 

 fly emit a peculiar odor by which they may be recognized. A segre- 

 gation of the sexes proved that the females do not emit this odor, 

 or at least that no odor can be detected. That given off by the males 

 is very evident and, while difficult of description, resembles somewhat 

 that of stale mucus. No odor can be detected until the males begin 

 courting the females, but from that time on it is sufficiently strong 

 so that during calm weather a person sitting as far as 4 feet from jars 

 containing adults is able to state whether the flies within are Ceratitis 

 capitata or Bactrocera cucurbitae . The latter species emits no odor. The 

 writers have attempted to make use of the odor emitted by the males 

 to trap the females in the laboratory and field, but in no instance 

 were females attracted to jars containing males, although the odor 

 eminating from the latter was pronounced. Males kept at 58° to 62° 

 F. neither courted the females nor gave off their characteristic odor. 



AGE AT WHICH MATING AND OVIPOSITION BEGIN. 



Adults, upon emerging from the pupa, must feed for several days 

 before they show evidences of sexual activities or begin oviposition. 

 Berlese, in Italy in 1905, published the first data bearing on this 

 subject. He states that the female does not oviposit until 10 to 12 

 days after emergence. Severin states that in Honolulu no fully 

 developed eggs were present in the ovaries of 3 females 8 days after 

 emergence. Although from the eighth day on he made daily dissec- 

 tions of 3 females, he found no mature eggs until the fourteenth day, 

 with the exception of a few in the ovaries of a single female 1 1 days 

 after emergence. The most careful observations appear to have been 

 made by Martelli, who states that females do not oviposit until 

 from 4 to 7 days after emergence during summer, or 10 to 12 days 

 during the autumn. Aside from Martelli's general reference to the 

 season, no writer has published along with his statements data on 

 temperatures, which the writers have found to be an important factor. 



The age at which the first eggs are deposited varies with the tem- 

 perature. During late July and early August, 1913, when the daily 

 temperatures at Honolulu ranged between 74° and 86° F., with a mean 

 for the period of 79° to 80° F., males began to show sexual activity 

 within 3 days, while mating and egg laying took place within 4 to 5 

 days. In securing infestation of fruits it was found that while few 

 eggs were deposited within 4 to 5 days after emergence, it was not 

 until 7 to 10 days after emergence that any lot of females seemed to 

 reach their full egg-laying capacity. These observations are based 



