THE MEDITERRANEAN FRUIT-FLY. 13 



LIFE HISTORY AND HABITS. 



The life history and habits of the Mediterranean fruit fly have 

 been very carefull}^ investigated by diiferent entomologists, par- 

 ticiilarl}' by Froggatt, French, Mally, and others. The following 

 account of the insect by C. W. Mally, entomologist for the Eastern 

 Province, is quoted from his article on " The Fruit Fly." which ap- 

 peared in the AgiTcultural Journal, Cape of Good Hope, December, 

 1901: 



Aside from an occasional query, nothing is heard of the fruit fly till the 

 maggots are nbqndant in the apricots and peaches. These maggots come from 

 eggs depositeil by the adult fly. 



The eggs. — The female is provided with a shai'p extensile ovipositor (the 

 organ through which the eggs are laid) which enables her to pierce the fruit 

 and at the same time deposit the small glistening white eggs just underneath 

 the skin — sometimes singly but usually a number together. They hatch in a 

 very short time, two to four days in midsummer. The ripeness of the fruit 

 seems to influence the rapidity of their development. It is difficult to get 

 relinble information on this point, for the mere fact that a fly is seen to pierce 

 the fruit is no proof that eggs are left at the same time. By opening the fruit 

 to make sure that eggs were deposited they are placed under unnatural condi- 

 tions. Different lots of eggs may be laid in the same puncture. I have ob- 

 served females in the act of ovipositlon and on immediate examination the 

 pulp was found to be discoloured and as high as ten eggs present, in some of 

 which the body segments of the larvte were distinctly visible under the micro- 

 scope. Although females may take advantage of slight injuries in the fruit 

 they are by no means dependent upon them, and evidently prefer sound fruit 

 in which to oviposit. Numerous examintitions of peaches, apples, lemons, 

 oranges, and pompelmoes, show that all eggs laid in fruit that is too green 

 perish as eggs, or, if they do hatch, the young larvfe perish almost at once. 

 This is an important point, for many fruit-growers take a hopeless view, 

 believing that the eggs may be laid in the fruit while it is still very young 

 and lie dormant until the pulp is sufficiently rii)e to serve as food for the 

 larvfe. It is of practical importance to those who enclose their trees with 

 netting, for it reduces the time the netting must be exposed to the weather. 

 Last March (1904) many apples were received showing a slight depression, in 

 the center of which was a small black speck. On close examination it was 

 found to be due to the fruit fly having ovipositetl, but no development followed. 

 The apples were still hard and the great mortality in the eggs, the shrivelled 

 remains of which could still be found, was considered to be due to the fruit 

 having been too green when oviposition took place. There was no trace of 

 parasitism. 



The larvje or "maggots" at once begin to feed on the pulp of the fruit. 

 In apricots they make straight for the center, the pulp evidently first ripening 

 round the pip. In peaches and other fruits they are moi'e incline<l to work out in 

 different directions from the point of oviposition, there being no distinct tendency 

 to penetrate towards the center. When fully developed, which usually requires 

 a fortnight or three weeks, they leave the fruit, which has as a rule fallen 

 several days previously, and enter the ground, seldom going deeper than one 

 inch, depending on the nature of the soil. Here they soon change to puparia, 

 and remain for twelve days to three weeks, depending on the season. When 

 the transformation to adult is complete the fly pushes through the end of the 



