8 SEVENTH REPORT OF THE FOREST, FISH AND CAME COMMISSION. 



busy and absorbed in devouring the crawlers that I could put my hand on them 

 before they started to fly, and then they merely flew to another tree close by, and 

 attacked another mass of caterpillars. 



" Blackbirds waddled over the grass by the sides of the streets picking up the 

 crawlers, and even a Woodcock spent several hours in the garden and on the 

 lawn, apparently feasting on tent-caterpillars, but I could not get near enough to 

 be sure. 



"The Vireos — White-eyed, Red-eyed and Warbling — the Cat-birds, Cedar-birds, 

 and Rose-breasted Grosbeaks did good service to the trees and human beings, but 

 the most evident destruction was done by the Chipping Sparrows when the moths 

 emerged late in the summer. The moths were very abundant after four o'clock in 

 the afternoon, flying about the trees to lay their eggs, and then the Chippies became 

 fly-catchers for the time, and flew straight, turned, twisted, dodged, and tumbled 

 ' head over heels and heels over head ' in the air, just as the course of the hunted 

 moth made necessary. A quick snap of the beak, and four brownish wings would 

 float down like snowflakes, and their numbers on the walks, roads and grass showed 

 how many thousands of moths were slain. In spite of the unwonted exercise the 

 Chippies waxed fat, but not as aldermanic as the Robins, which, earlier, gorged 

 themselves on the caterpillars until, as one observer said, ' their little red fronts 

 actually trailed on the ground.' " 



The extent to which trees are subject to attack and their consequent need of 

 insect destroyers may be more clearly understood if we consider for a moment the 

 life of a tree in connection with the insects th.it prey upon it. Let us take, for 

 example, the oaks of the genus Oucrcusr At the very beginning, before the acorn 

 has germinated, it may be entered by a grub of the nut weevil {Balaninus) which 

 destroys it, and the more or less empty shell becomes the abiding place of the larva 

 of the acorn moth. Should, however, the acorn be permitted to grow, the roots of 

 the young tree may be attacked by the white grubs of root-boring beetles. Escap- 

 ing these, the oak carpenter worm (Prionoxystus) lays its eggs in cracks and crevices 

 in the bark. On hatching, the worm or borer " perforates a hole the size of a half- 

 inch auger, or large enough to admit the little finger, and requiring three or four 

 years for the bark to close together over it. This hole, running inward to the heart 

 of the tree, and admitting water thereto from every shower that passes, causes a 

 decay in the wood to commence, and the tree never regains its previous soundness." 

 ( Fitch.) 



Other borers (Buprestidm) feed upon the bark, eating the soft inner layer and 



* See Packard, lorest Insects, Fifth Report U. S. Entomological Commission. 



