Feb. 



Mediterranean Fruit Fly 



371 



after emergence that one is likely to be discouraged in obtaining eggs. 

 While the sexes of the Mediterranean fruit fly are sexually active through- 

 out the day, the melon flies become active only at sunset. From sunset 

 until dark copulation occurs and lasts in many instances until daybreak, 

 inasmuch as numerous pairs have been observed in coition at midnight 

 and at dawn, when all flies are very quiet. Adults issuing from pupae 

 on May 24 did not mate until June 13, or 20 days after emergence, 

 although they were observed every evening. The majority of females 

 in this lot did not mate until 25 days old. The daily mean temperatures 

 for the period from May 24 to June 13 averaged 75.5° F. 



The female Bactrocera cricurbitae is more irregular in her habits of 

 oviposition. As shown by the data in Table IV, she lays more con- 

 sistently a large number of eggs at one time. 



Table IV. — Daily rate of oviposition of the melon fly (Bactrocera cucurbitae). Emerged 

 on May 2J atid placed separately with fruit on June 25, IQI4<' 



Number of eggs deposited. 



Date of oviposition.*' 



July 10. 



II. . 



15 •• 

 17.. 

 18.. 

 19.. 

 21. . 

 22. . 



23- 

 24.. 

 26.. 

 27.. 



Fly No. I. Fly No. 2. 



2g 



Fly No. 3. 



o 



13 

 o 



9 

 o 

 o 



o 



Fly No. 4. 



Fly No. s. 



10 

 o 

 o 

 o 



Fly No. 6. 



23 

 o 



12 

 o 

 o 

 o 

 6 

 o 

 o 

 o 



23 



Fly No. 7. 



o 

 o 

 o 

 o 

 o 



19 

 o 

 o 

 o 

 o 

 o 



. o 



a These 7 females were all alive on July 27. 



& Dates on which none of the flies oviposited are omitted from the table. 



The data in Table IV were secured from young females during the early 

 period of sexual activity. Other data on file show that females over 5 

 months old deposit quite as freely. 



EGGS 



Eggs may be obtained most easily for experimental work by suspend- 

 ing fruit on a string in a jar containing adults, after the latter have begun 

 to mate. In Plate XLV, figure i, is illustrated this simple method of 

 obtaining eggs during a known period. If the epidermis of the fruit is 

 shaved off in several places oviposition will be made easier. The 

 removing of eggs either from the body of the female or from the sides of the 

 containing jar, as practiced by several workers, has not given good results. 



If it is desired to keep constant watch over eggs they may be dissected 

 easily from the egg cavity and spread upon a section cut from any firm 



