INSECTS AND PLANTS S3 



fruit into a brown jelly which often exudes from the 

 puncture and hardens. This, at least, is the usual happen- 

 ing, though all fruits are not similarly affected: green 

 oranges ripen prematurely around the puncture, but, in 

 some unripe fruits, the secretion of the female fly prevents 

 further ripening around the puncture, with the result that 

 a depression is formed on the exterior of the fruit. 



Swift retribution sometimes overtakes the mother fly, 

 for she is not always able to withdraw her ovipositor from 

 the fruit ; then she falls an easy prey to marauding lizards, 

 or, worse case still, she dies of starvation. The duration of 

 the egg stage varies, according to whether oviposition has 

 taken place in ripe or unripe fruits ; in the latter event the 

 eggs take longer to hatch. Sometimes, too, the eggs hatch, 

 but the larvae promptly succumb to the effects of the acids 

 in the fruit juices ; this is the case in the Chinese banana, 

 whose unripe juices are rich in tannic acid. In the event 

 of no such fate overtaking the maggots, they bore their 

 way into the pulp of the fruit, which begins to decay and 

 eventually falls to the ground. After a variable number 

 of days spent in the fruit, the maggots eat their way out 

 of the rotting fruit and enter the ground to pupate. The 

 period of the larval stage varies with the temperature, 

 moisture, kind of fruit, its hardness, rate of decay, and 

 acidity. The pupal stage lasts for rather more than a 

 fortnight, after which the adult flies emerge. Egg-laying 

 does not begin at once ; a period of ten or twelve days is 

 necessary for the adults to attain maturity, and during that 

 time they subsist on various sugary substances. 



Whilst America is indebted to Europe for a large number 

 of her most destructive insect pests, accounts have been 

 somewhat balanced by the introduction of the grape vine 

 phylloxera, Phylloxera vaslalrix, from the United States. 

 This noxious insect is a native of the United States, east 

 of the Rocky Mountains, where, for years, it had lived 

 almost unnoticed on the wild vines. About the year 1859 



