The Apjyle. 



53 



scales, or within cracks and crevices of the hark. These 

 soon hatch aud the 3'oung larva eats its way into the sap 

 wood, where it excavates broad channels. A single speci- 

 men will sometimes girdle a small tree. The insect is sap- 

 posed to pass its transformations in one year. 



Preventive measures. The trees should be examined in 

 early fall for this insect, when the yonng larva, if present, 

 may often be detected by discoloration of the bark, by a 

 flattened or dried appearance of the bark over its burrow, 

 or by the presence of sawdust-like castings adhering to the 

 bark. The larva (a. Fig. 13) may be cut out with a knife, 

 or the burrow may be probed with a 

 wire or flexible twig. Coating the 

 bark with the soap mixture previ- 

 ously recommended (57) aids in pre- 

 venting the entrance of the larva. 



The flat-headed borer is most likely 

 to attack trees of which the bark 

 has already been injured by sun-scald 

 or otherwise. 



59. The oyster-shell bark-louse 

 [Mytilaspis jJomorum) (Fig. 14) af- 

 fects the apple, pear and quince 

 fruits throughout northern United 

 States and Canada. It is most inju- 

 rious to unthrifty trees. The scales, which cover the eggs 

 of the insect, are about one-sixth of an inch long. They 

 are colored like the bark and are shaped somewhat like an 

 oyster shell. They are mostly attached to the smooth bark 

 of the younger branches and are sometimes so numerous as 

 to almost conceal the bark. The eggs hatch late in May 

 or early in June, when the lice, which are so small as to 



Ftg. 13. Flat-headed apple- 

 tree borer. A, larva as it ap- 

 pears in tree; b, chrysalis; 

 d, perfect insect. (After 

 Satmders.) 



