4 6 4 BULLETIN 388 



as late as October 7. After that date they could not be found on the trees 

 in the writer's experimental plot. They are sluggish, very inactive insects, 

 and move with a slow, lumbering gait. When they are disturbed, either 

 by being jarred or by any sudden noise, they do not fly but feign death 

 and drop to the ground, the beak and the legs being closely drawn against 

 the body. They remain quiescent usually for a minute or two before 

 attempting to crawl away. When handled they emit a squeaking noise, 

 produced by the rubbing together of parts of the body. Though close 

 watch for it has been kept, flight has not been observed, and no one 

 has recorded the beetles as spreading by means of flight. Whether or not 

 they are incapable of flight the writer has not been able to determine. 



Shortly after the beetles emerge from the pupal cells they begin to 

 feed, selecting young, tender shoots. The bark is punctured by the 

 beak, a round hole being formed down to the cambium layer, on which 

 the beetles largely feed. The beetles are voracious feeders, and when they 

 are abundant the young one-year-old shoots may be so completely 

 riddled by the feeding punctures that they shrivel and die. So far as 

 the writer's observations go, the beetles do not feed on old bark, 

 but confine themselves to the young and succulent twigs. Punctures 

 in old bark are for the xieposition of eggs, and these always appear some 

 weeks after the beetles have been feeding. 



The beetles do not seem to migrate to any considerable distance. 

 Although the wings are perfect and apparently suitable for flying, yet 

 the beetles have never been observed in flight or attempting to fly. In 

 the nursery it is not uncommon to find one block badly infested, whereas 

 a block somewhat distant may be only slightly injured. Change of loca- 

 tion in the growing of poplars from year to year frequently makes a 

 marked difference in the degree of injury. One block of about 15,000 

 trees in a large nursery near Geneva had an infestation of nearly 50 per 

 cent in 1915. A block of about the same number of trees situated three- 

 fourths of a mile distant showed in 1916 only a small infestation, 3.5 per 

 cent, in the check rows. The beetles were abundant in 1915 in the block 

 ready to be dug, and apparently they had confined their egg-laying oper- 

 ations to the poplars from which they had emerged. As this is true in 

 all the cases coming under the writer's observation, it can readily be seen 

 that a block ready to be dug, showing only a small percentage of infes- 

 tation, may make an ideal center for distribution. As the nurseryman 

 discards only severely injured stock, a block with such a low percentage 

 of injury will practically have all the trees fit for sale, and in this way 

 every egg deposited will be shipped away to start new infestations. 

 When trees show considerable injury they are discarded and burned 

 (% 113)- 



