14 THE MEDITERRANEAN FRUIT-FLY. 



puparium and works its way up tlirough the soil. Ou reaelniig the surface the 

 wings expand to full size, and in a short time the fly is ready to search for 

 food. They are fond of the exuding juice of injured fruit. After mating they 

 lay eggs and die, thus marking the end of one generation and the beginning of 

 the next. The eggs are not all deposited at once. Just how long the im- 

 pregnated female lives and continues to lay eggs under natural conditions is 

 'not known, but it is several weeks at least. 



The number of broods in a year depends on circumstances of food supply and 

 temperature. In midsummer, with abinidant food, they develop more rapidly, 

 one generation being complete in about twenty-eight days. Very ripe fruit 

 seems to hasten their development. During the winter, at Grahamstown [Cape 

 Colony, S. Africa], they require two months or more to complete their trans- 

 formations. The puparium stage of the midwinter brood, recorded below, 

 required thirty-five days in the rearing-box in the office at the ordinary sea- 

 sonal temperature. The broods overlap to such a great extent that it is im- 

 possible to keej) them separate in the field. 



With the ajtpi'oach of winter, the females are able to survive several months 

 under natural conditions if no suitable fruit is available for egg deposition. 

 The late peaches furnish the last grand feast, about the first of April. The 

 adults of this generation emerge early in May and can survive till the citrus 

 fruits are sufficiently ripe to serve as food for the larvae. 



In this article Mr. Mally adds that the adults are keen feeders, 

 taking readily to the juice exuding from the injured or decaying 

 fruit, and some individuals have been found to feed on the lioncy- 

 dew from certain scale insects. It is the consensus of opinion that 

 the insect is carried from one locality to another by means of infested 

 fruit. TTlien once introduced in a localitj^, however, there will be a 

 natural spread or dissemination of the species, though the rate of 

 disseminat'on has not been ascertained. This will doubtless vary 

 u-ith the climate in question, particularly with the strength and 

 direction of the winds. Migrations will be stimulated by an insuf- 

 ficiency of food supply. 



DESCRIPTION. 



The following description of the adult is quoted from Farmers' 

 Bulletin 24, Department of Agriculture of New South "Wales, by 

 W. W. Froggatt : 



Size 4 to 5 mm., about the size of an average house-fly, but looking somewhat 

 smaller when dead, because the body shrinks up beneath the thorax. General 

 color, ochreous yellow, lighter on the sides of thorax and basal joints of the 

 anteuaae. The eyes of the usual reddish puri^le tint, with a blackish blotch 

 in the center of the forehead, from which spring two stout black bristles, a fine 

 fringe of similar bristles round the hind margin of the head, with some coarser 

 ones curving round in front of the head between the eyes. The thickened basal 

 joints of the antennte pale yellow, the terminal segments black to the tips. The 

 dorsal surface of the thorax convex, raised, and broadly rounded with the 

 ecutellum, the ground color creamy white to yellow, marbled with shiny black 

 blotches forming an irregular mosaic pattern, the lighter portions clothed with 

 very fine white bristles. These light-colored bristles more lightly scattered 

 over the dark areas, and the whole bearing large stout black bristles thickest 

 ou the black surface. 



