112 FLORIDA FRUITS ORANGES. 



the surface of every orange showing rust will be found 

 thickly sprinkled with them, and we shall be forced to 

 conclude that we have before us the relics of a numerous 

 colony, which at some former period infested the fruit. 



Extending the examination to fruit that as yet shows 

 no indication of rust, we will, if the season is not too far 

 advanced, obtain abundant confirmation of this conclusion, 

 and find these colonies in the full tide of their existence. 

 The former occupants of the cast skins prove to be elon- 

 gate mites, of honey-yellow color, too minute to be seen as 

 individuals with the unassisted eye, but visible in the 

 aggregate as a fine golden dust upon the surface of the 

 fruit. 



The Mite on the Leaves. Having tracked the mite by 

 means of its tell-tale exuviae, and detected it at work upon 

 the fruit, if we turn our attention to the leaves it needs 

 no prolonged search to discover it here also, and in even 

 greater abundance. In fact it is evidently upon the leaves 

 that the mites exist and propagate throughout the year ; 

 for not only are they found upon fruiting trees, but upon 

 plants of all ages, in the nursery as well as in the grove. 



Nothing resembling the rust of the fruit follows their 

 attacks upon the leaves. Each puncture of the mites 

 gives rise to a minute pimple or elevation, until the sur- 

 face of the leaf becomes finely corrugated, loses its gloss, 

 and assumes a dusty and corroded appearance. 



This tarnished appearance of the foliage is very charac- 

 teristic, and remains a permanent indication of their dep- 

 redations after the mites themselves have disappeared. 



First Appearance of Mites on the Fruit. From the time 

 when the cellular structure of the rind has completely de- 

 veloped, and the oil-cells have begun to fill, until the fruit 

 is far* advanced into the process of ripening; in other 

 words, from early spring until late in autumn, it is liable 



