434 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



and winter will destroy many of the larvae and pupae that are 

 in the ground. 



The Pear- leaf Blister-mite (Eriophyes pyri}. This little 

 mite, that causes red blister-like blotches on the leaves of the 

 pears and sometimes of the apples, is not an insect, as is 

 commonly supposed, but is an Arachnid and is discussed on 

 page 213. 



The Peach Borer (Sanninoidea exitiosa). This insect is 

 probably the most important of those that attack the trunk 

 of orchard trees. Not only the peach but the apricot, plum, 



FIG. 207. California peach-tree borer, larva of Sanninoidea opalescens, 

 in cocoon. (About natural size.) 



prune and nectarine may be seriously affected by it. The eggs 

 are laid on the outer bark near the base of the trunk. The 

 larvae burrow in and feed on the inner bark usually close to the 

 surface of the ground. Their presence is indicated by gummy 

 exudations mixed with the castings of the larvae. Several 

 larvae feeding on a tree may completely girdle it or so weaken 

 it that it will bear little fruit and be much more subject to 

 the attacks of other insects or diseases. Much of the sawdust- 

 like castings and bits of bark are incorporated in the cocoon 

 which the larva spins in the end of the burrow or on the surface 

 of the tree, or in the ground close to the surface. The adult 



