ENEMIES OF THE FOREST. 



247 



Fig". 101. Work of the Columbian Timber Beetle in 

 Tulip Wood, "Calico Poplar." {Aerie. Tear Book 



\_Agt 

 1903, FijLf. 40, p. 326.] 



pests. The most destructive are the prcdaceons and parasitic insect-- 

 Many insects are simply predaceous, pouncing upon and destroying 

 such other insects as they can overcome. 

 Still others are parasites, some external, 

 but most of them living within the bod- 

 ies of their victims where they pass their 

 entire larval life. The eggs are laid on 

 or in the body of the victim, so that as 

 soon as one hatches, it has suitable food. 

 The ichneumon fly, Fig. 103, is such a 

 parasite; it destroys millions of insect 

 pests. It has a long and peculiar ovipos- 

 itor with which it drills a hole into the 

 tree and deposits the egg in a burrow of 

 the Pigeon Horntail, a wood wasp that 

 burrows into deciduous trees. The larva 

 soon finds its victim, the grub of the 

 Pigeon Horntail, and lives on it to its 

 destruction. 



It would seem that it is a hopeless 

 task to control the insect enemies of for- 

 est trees and forest products or to pre- 

 vent losses from their ravages, but the 

 writer is informed by Dr. A. D. Hopkins, Fig-. 102. work of ih e r arp en- 



,1 j. 1 1 -n 1er Bee, Xylocopa orpifex, in 



tlie expert in the -Bureau OI Entomology Redwood Lumber: a, entrance; 



-,,. *, g-alleries; c, cells; ct, larva; 



in charge 01 lorest insect investigations e > adult. [Agrfc. Tear Book, 



1904, Fig. 53, p. 390.] 



