SEM1TROPICAL FRUITS 165 



these insects along the large veins. Here they insert their 

 beaks and suck the sap which is being carried upward to 

 the leaves and the prepared food which the leaves send 

 downward to the other portions of the plant. Scale insects 

 are also sometimes found on the fruit itself. 



If the tree is sprayed with an emulsion of kerosene or 

 is fumigated with 

 hydrocyanic acid 

 gas, these insects 

 will disappear. 



Red Spider. In 

 some places where 

 these fruits are 

 raised the red 



FIG. 93 Red Spider. (From Station Bulletin, Berkeley, Cal.) 



spider has become 



a serious pest. The male spider is much smaller than the 

 female. The female lays from twelve to eighteen bright 

 red eggs, which are fastened to the under side of the leaf 

 with threads of fine silk. These eggs hatch out in about 

 two weeks, and the young spiders begin at once to suck 

 the juice from the leaf. When grown, their bodies are 



covered with spines, which 

 protect them from their ene- 

 mies, the ladybird beetles 

 and the lace-wing flies. 



White Fly. This pest of 

 FIG. 94. white Fly with wings Extended, citrus trees was unknown in 

 California until a short time ago. As yet it has appeared in 

 but a few places. Although called a fly, it is not one, since 

 it has four wings, and the fly has only two. It is a near 

 relative of the scale insects, but it does more damage because 



