80 



Description : Length, 3 lines ; expanse of wings, 5 to 6 lines. The perfect fly 

 has clear transparent wings, clouded very slightly, clouded along the costal 

 nervure, and a tine tran verse fuscous stripe crosses the- wing towards the 

 base ; the nervures reddish. The abdomen, constricted at the base, is broadly 

 rounded to the tip, furnished with a fine ovipositor in the female, while 

 that of the male is more elongated, so that the female is more wasp like in 

 form than the male. 



In general coloration they are somewhat variable, but on careful exami- 

 nation the yellow markings will be found constant ; but this has led to some 

 confusion in determining the species, when they have been bred from 

 nncommon fruits or vegetables. Head : The eyes almost black ; face, with 

 rounded black spot on either side below the antennae ; tips of antennae fuscous, 

 and a few indistinct spots or marks on the forehead ; thorax, wi' ha broad 

 creamy often pale dorsal band, running down to thejscutellum, with a short, 

 well-defined narrow pale yellow stripe on either side. On the sides of the 

 thorax there is a small, rounded, creamy white spot in front, with a blotch 

 formed of two parts of the same colour in a line with the front of the 

 parallel side stripe; the scutellum, white to pale yellow, is prominent, some- 

 what convex on the upper surface, broadly angulated behind, with two stout 

 Bristles. The legs are pale yellow, tarsi darkest ; abdomen, blackish to 

 brown, with a broad transverse band of pale dull yellow across the basal half. 

 The bristles on the antennae are long, with fine scattered bristles on the head 

 and sides of the thorax, and the abdomen finely pubescent. 



It is, in the first place, a typical orange fly, then a banana pest ; but there 

 are few fruits that it has not been bred from at some time or other. It is 

 closely allied to the Indian Mango Fly, Dacus ferrugineus, described by 

 Fabricius, and ranges from India and Ceylon to Java and Amboina. 

 Though commonly a mango pest, it attacks and destroys many fruits. 



In the Journal of Agriculture, Victoria, May, 1907, French published an 

 article entitled " Fruit Flies," afterwards issued as Bulletin 26 of the 

 Department of Agriculture, Victoria. In this paper he describes a variety 

 of D. tryoni under a varietal name of Dacus cucumis, the maggots of which 

 were obtained in large quantities from cucumbers imported from Queensland. 

 I, have carefully compared specimens kindly given to me by Mr. French, and 

 others that we have bred from cucumbers that were sent from Coonamble, 

 New South Wales, and consider it may rank as a species. There are no 

 differences in the wings, but the whole insect is of a much lighter colour, and 

 has a well-defined short, broad, pale yellow blotch or stripe in the centre of 

 the lower half of the dorsal surface of the thorax, while the side stripes of 

 yellow on either side are shorter, broader, and more curved. 



There is, apparently, another variety, if not a distinct species, that breeds 

 in tomatoes grown in Queensland. 



Another variety, also found breeding in tomatoes from Queensland, has 

 two well-defined blackish parallel lines down the sides of the dorsal surface 

 of the thorax, which run into each other behind the head, with the silvery 

 pubescence enclosed between them. 



At the same time, I have typical specimens of the Queensland fruit-fly 

 without the central yellow blotch, also bred from tomatoes. 



Probably other members of this genus will be found in the northern 

 portion of Australia, when carefully looked for, as the genus has a wide 

 range. 



