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PART III. 

 Fruit Flies. 



A general account of the flies belonging to the family Trt/petidce that damage sound fruit, 

 with descriptions of the different species (some described as new), and their habits, 

 range, and suggestions for destroying them. 



THE group of insects known as " Fruit Flies," though so much before the 

 public at present, need some definition, for it is a common thing for the 

 orchardist to assume that any small fly hovering round damaged or rotting 

 fruit is the "fruit-fly" and any maggot in the mass to be the destructive 

 fruit-fly maggot. In a great many cases the latter are species that have no 

 connection with the true pests, that never damage sound fruit, and are 

 simply attracted by the decaying matter, and really act as scavengers. The 

 fruit-flies are a well-defined group of the order Diptera (two-winged flies), 

 and belong to the family Trypetidw. 



This family comprises a large number of rather small flies, usually with 

 mottled or banded wings ; they are remarkable for their curious habits in 

 the larval state in producing galls upon plants, or in mining in the tissue of 

 the stems, leaves, or flowers of different plants, or in the flesh of ripening 

 fruit. The females, with their % needle-like ovipositors, puncture the plant 

 and deposit the eggs beneath in the tissue. 



In Australia we have a number of indigenous species that form galls ; but 

 the group that we are dealing with here are those that have the habit of 

 depositing their eggs in the fruit of wild or cultivated plants, and comprise 

 some of the most serious pests that the orchardist and gardener have to fight 

 against. Some of these are cosmopolitan and are found in many countries, 

 while others are restricted in their range ; but whenever a species attacks 

 cultivated fruit it can very easily be introduced into a new country, either 

 in the larval (maggot) or pupal (chrysalis) stage. 



Eggs deposited in fruit may be transported in apparently sound fruit and 

 on transit may develop days afterwards, or the more or less developed 

 maggots may reach maturity, crawl out of the fruit, and pupate in a crevice 

 in the case or among the packing, and then after the contents of the case 

 have been destroyed it may develop, emerge as a perfect fly capable of doing 

 untold damage. There are records proving that the pupae have been found 

 in the soil round the roots of imported plants that have been grown in 

 infested districts. 



The destructive species of the family Trt/petidce have been described by 

 many entomologists, and are comprised in about half a dozen genera. In the 

 north-eastern States of North America there are two common orchard pests 

 which, originally placed in the genus Trypeta, have, after closer examination, 

 been placed in the genus Ragoletis,^ group of small flies with four bristles on 

 the scutellum and black cross bands on the wings. The apple maggot 

 (Ragoletis pomonella), a native of North America, where it fed upon haws 

 and crab apples growing in the forests, is often a very serious apple pest in 

 New York State. When I was at Cornell University, Ithaca, in the early 

 partf of October, the apples growing on the College campus were full of 

 maggote. A second species (R. cerasi, "The Cherry Fruit Fly ') has a 

 similar range in the United States, sometimes causing considerable damage 



