FRUIT FLIES 47 



meanwhile been enlarged by other insects, may become 

 conspicuous objects, and the more so when, as often 

 happens, they are surrounded by altered brown tissue. 

 : 'It may happen, also, that the surface of the fruit 

 may be rendered uneven, and this is especially so when 

 the latter has been early attacked. The following 

 description of an infested apple may be taken as an 

 illustration : 



' In this case the surface of the apple appeared to 

 have been stung all over, and although most of the holes 

 caused by the punctures were now obliterated by 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 color 

 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 prevails, or the depressions, are largely devel- 

 oped on one surface of a fruit, this becomes very 

 unsymmetrical in shape. It sometimes happens that 

 pears and apples when still green and hanging on the 

 tree develop well denned patches or spots of a coffee- 

 brown color ; these are found to be deep-seated and to 

 be attended by the presence of a fungus. 



' In several instances of fruit so affected we have 

 detected the maggot of the fruit-fly, by breeding the 

 latter from such specimens, but in quite as many 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 by this pest ; but such may afford 

 the antecedent circumstances favorable to its establish- 

 ment. 



4 An infected pear when cut through, though it may 

 show no sign of internal injury, will exhibit numerous 

 brown spots of different size, the sections of as many 

 channels whose walls are composed of altered brown 

 tissue, aud which sometimes are the centres of much 



