I X SECTS AFFECTING PARK AND WOODLAND TREES 593 



incision made by the insect would heal over and cause little after-damage, 

 but the combination of the two incisions and the killing of the intervening 

 bark causes it to ^adhere to the wood and a large scar is produced, which 

 with subsequent years' growth assumes an oval form, the dead bark of the 

 center breaking out. Limbs which have been thickly worked by the insect 

 become very scabby and rough, are easily broken off by the wind, and are 

 very liable to attack by wood-boring insects. The adults appear about the 

 middle of July and become most numerous during August and September. 

 They begin oviposition about the middle of the former month, or even 

 earlier, and continue till they are killed by the frost of early winter, some- 

 times working as late as the end of October. The number of eggs 

 deposited by a single female exceeds 100, and possibly 200. The eggs 

 remain unchanged or dormant in the twigs till the following spring, 

 hatching in May or early in June. 



Food plants. The young as well as the adults feed on all sorts of suc- 

 culent vegetation, such as weeds and garden vegetables, and are apparently 

 not particularly fond of the apple, much preferring the more succulent 

 annual plants. Mr J. G. Jack states that he has found the adults feeding 

 on the young tender shoots of the apple near the ground, though Dr Mar- 

 latt states that after careful and repeated observations in an orchard, so 

 badly infested as to be nearly ruined, he failed to find any indication of the 

 insects feeding on the apple, and he concludes that the infestation that 

 Mr Jack observed must relate to the suckers springing from the base of 

 the tree. 



Distribution. This insect has evidently a very general distribution in 

 the United States, since it has been recorded from Canada, southward to 

 Missouri, at least, and westward to the Rocky mountains. 



Bibliography 



1897 Marlatt, C. L. U. S. Dep't Agric Div. Km. Cir. 23, 2d s. 



