8 May, 1907.] Fruit Flies. 311 



" Other fruit, especially the pear, often alsoi appears quite sound too, 

 though it has afterwards been found to be maggot eaten. Usually, how- 

 ever, there is some external indication — ^one side of a peach may appeal 

 dull green as if slightly bruised, and the surface of a pear or plum may 

 exhibit at spots the appearances which would follow a similar injury to these 

 fruits. At these places it will be found that the fruit is softer than at 

 others, and that generally the juice will exude on pressure at one or two 

 minute holes, which, however, in the case of the peach, may have tieen 

 previously detected, especially when occurring in the lateral depression. 



"At a later stage, these punctures, in each of which an egg has been 

 deposited by the fruit fly, having meanwhile been enlarged by other 

 insects may become conspicuous objects, and the more so when, as often 

 happens, thev are surrounded by altered brown tissue. 



"It mav' happen, also, that the surface of the fruit may l)e rendered 

 uneven, and this is especially so when the latter has been earlv attacked. 

 The following description of an infested apple may be taken as an illustra- 

 tion : 



'• In this case the surface of the apple appeared to have been stung 

 all o\er, and althoug'h most of the holes caused by the punctures were now 

 obliterated b\ the growth of the fruit itself, there was abundant evidence 

 of the extent of the injury. The site of the puncture was marked by a 

 minute dark spot, surrounded by a small halo of a darker green than was 

 the general colour of the unaffected parts ; these spots were each of them 

 the centres of shallow depressions ; these depressions were sometimes 

 confluent. In cases where the last condition i)revails, or the depressions 

 are largelv developed oji one surface of a fruit, this becomes very un- 

 symmetrical in shape. It sometimes happens that pears and apples when 

 still green and hanging on the tree de\-elop well defined patches or spots 

 of a coftee-brOiWii colour ; these are found to te deep-seated and to be 

 attended bv the presence of a fungus. 



"In several instances of fruit so affected we ha\e detected the maggot 

 of the fruit-fl\. by breeding the latter from such specimens, but in quite 

 as man\ others have failed to do so, and this being the case we are not 

 disposed to regard this canker-like disease as being due to injuries inflicted 

 bv this pest ; but such ma\- afford the antecedent circumstances favorable 

 to its establishment. 



"An infected pear when cut through, though it may .show no sign of 

 internal injur\-, will exhibit numerous brown spots of different size, the 

 sections of as man\- channels whose walls are composed of altered brown 

 tissue, and which sometimes are the centres of much more extensive injur\ . 

 At other times a zone of brown tissue surrounds the core. In a peach 

 or in a plum the maggot seems to find its way very quickly to the stone, 

 and then to feed on the tissue immediately surrounding it, usually to a 

 greater extent on one side than the other, devouring the pulp, leaving the 

 more fibrous material, and producing generally much semi-fluid matter as 

 a product of decay. In a free-stone peach the symptoms usually com- 

 mence in the tissue immediately adjacent to the stone; but in a cling- 

 stone the injurv seems for some time to be frequently limited to the part 

 opposite the lateral depression, and between it and the stone. _ Eventually 

 all fruit which is attacked becomes a mere 'mass of corruption.' It_ is 

 im.portant to note, however, that the fruit maggot never attacks the pips 

 or stone of a fruit nor vet the rind." 



Mr. Tryon further remarks: "It is the general opinion in the district 

 (toowoomba) that cultivation has no influence in protecting the trees from 



