204 Journal of Agricultural Research voi. xxn, no. 4 



former, so far as the Forest Insect records are concerned, feeds only in 

 pine (Pinus) and spruce (Picea), and for this discussion will be confined 

 to the form occurring in the northeastern United States. It shows a 

 decided preference for a certain condition of the host, requiring wood 

 that has been cut in the early fall or winter and is well seasoned. When 

 the inner bark is still sappy the insects will not normally make their 

 attack. 



Adults first appear about the middle of April, and the flight period 

 continues about a month. One year is required to complete the life 

 cycle. The larvae feed beneath the bark until half grown, then enter 

 the wood to construct a long pupal excavation, at the end of which the 

 pupal cell is chambered off. 



These experiments were started in December, 19 16, when infested 

 Virginia pine was caged. In 19 16 and the following years the colony 

 was continued in seasoned pine, and a form was also developed in spruce 

 and freshly cut or green pine. Unsuccessful attempts were made to 

 produce a juniper (Juniperus) strain. This insect has been reported as 

 feeding in juniper (Juniperus) and maple (Acer). 



Juniperus. Experiment IV^ — In April, 19 16, juniper was placed 

 in the cage together with pine; in addition, about 20 adults were isolated 

 on a stick of juniper (both woods were cut in January, 19 16). In neither 

 case was the juniper attacked, and the females isolated on juniper failed 

 to oviposit. 



The same test was repeated in 191 7 with juniper cut in October, and 

 the same results were obtained. During June and July, 20 larvae, from 

 small to over half grown, were transferred to juniper. All finally died, 

 some living a month. None increased in size before death. 



Picea. Experiment IV^. — April 12, 1916, a piece of seasoned 

 spruce was placed in the cage, together with the pine, for reinfestation. 

 An examination in June showed only one larva in the stick, and this was 

 far below the normal size of those in pine. By July 11 this larva had 

 died. It is possible that more eggs were laid on the spruce but the larvae 

 died earlier. 



June 29, 1916, nine larvae about half grown were transferred to the 

 same spruce wood. July 11, 191 6, three larvae were alive and 17 more 

 were transferred. From these larval transfers 10 adults were secured 

 in April, 191 7. They were caged on four small pieces of seasoned spruce 

 and a piece of seasoned pine placed in the cage for one week, both cut in 

 October, 19 16. Examination in July showed the spruce well infested, 

 but only 4 larvae were found in the piece of pine. 



In 19 1 8 the same experiment was repeated, four females and three 

 males from spruce being caged on four sticks of spruce and one of pine 

 cut in September, 191 7. An examination in July showed that the spruce 

 contained many larvae, but none were found in the pine. 



