as "chip-cocoons." Within these cocoons which may lie either 

 near the surface of the sap wood or in the pith, each larva 

 changes into the state known as the pupa, which requires no 

 food and is capable only of feeble movements of the abdomen. 

 The insect remains in this stage for a period which varies with 

 conditions of temperature and moisture. This transformation 

 in the region of Orono was at its apex during the season of 

 1919 in the latter part of July, although a few of the insects 

 were still larvae in the middle of August. The first adults of 

 the new generation were obtained July 30, but these were but 

 recently transformed from the pupae and from a considerable 

 number of infested leaders which were under observation, no 

 adult emerged before August fifth. The adults continue emerg- 

 ing from the old hosts throughout the month of August and to 

 decreased degree during early September, while a few derived 

 from eggs laid late, pass the winter in the old leaders either as 

 larvae or as young immature adults. By far the greater number, 

 however, emerge before September and on the approach of cool 

 w T eather, seek some sheltered place in which to pass the winter. 



The leader which has been attacked at first shows no signs 

 of injury aside from the exudations of pitch already mentioned. 

 The new growth begins normally, but soon after the larvae be- 

 gin feeding, the new growth above the injury begins to wilt, and 

 soon turns brown and dies. As the larvae continue f ceding, the 

 terminal continues to die farther and farther down and usually 

 the entire leader down to the first whorl of laterals is killed. 

 Occasionally, when the number of larvae is greater than usual, 

 they may continue their work of destruction below the upper 

 whorl of laterals. In this manner, two years ' growth and rarely 

 three years' growth is killed. 



The killing of the leader in this manner throws the vitality 

 of the tree into the next group of laterals below the injury. 

 These turn upward ; each develops a more or less strong growing 

 tip, and they all contend for leadership. If these new leaders 

 are not again attacked the result is the production of a forked or 

 branched top, known among woodsmen as a "stag-horn pipe." 

 This either much decreases or entirely destroys the timber value 

 of the tree, and at the same time detracts from its beauty. How- 

 ever, very often the new leaders may be attacked year after 

 year, resulting in the production of a stunted, bushy growth 



