October, ’23] 
FOREST ENTOMOLOGY IN UNITED STATES 
419 
natural forces can be utilized and by rapid transportation of green saw 
logs from the woods into the water at the mill pond or to sites in full 
sunlight, as worked out by Dr. Craighead and other members of the 
division of Forest Insects, damage by borers and ambrosia beetles can 
be prevented. Green lumber can be protected from attack by the 
removal of bark edges and loose piling. 
Future Needs 
While Dr. Hopkins and his staff of forest entomologists have chiefly 
concerned themselves with what have been deemed the most important 
and most pressing demands from timber holders for information on the 
insect enemies of forests, tree-killing barkbeetles that take a large 
annual toll in healthy merchantable timber, and insects infesting forest 
products where handling has increased the value of the material; it is 
true that there exist many problems of comparatively lesser importance 
which still remain to be solved. Among the most important of these 
are the defoliators. However, it is also true that this type of insect 
forms the most fluctuating and least constant menace. The caterpillars 
and false caterpillars responsible for those sporadic losses which are 
admittedly great are still not truly constant primary enemies of the 
great bulk of our timber. Death of the defoliated trees is sometimes 
due to secondary attack. As a consequence, the defoliators have, for 
economic reasons, had to yield to the continuous pressure of their more 
dangerous and destructive rivals. 
Close cooperation between foresters and forest entomologists in the 
study of the possibility of silvicultural and management methods of 
control of these defoliating insects—as has been begun in Canada—will 
yield valuable results. 
Summary 
Dr. Hopkins has contributed to the progress of the science of Forest 
Entomology in at least three distinct ways: He has advanced to a remark¬ 
able extent our knowledge of tree-killing beetles as systematist, biologist 
and morphologist on Scolytid beetles of the world, on which he is 
recognized as a world authority; established principles of fundamental 
importance for the economic control of forest insects; organized, led and 
developed an extraordinary staff of assistants and specialists in the vari¬ 
ous fields of Forest Entomology. Indeed in the latter connection, while he 
himself leaves this field the work in which he has so aided, there remain 
many workers, who, guided and inspired by him, have added much to 
the knowledge of the problems of Forest Entomology. We may look 
