I 



UTILITY OF BIBBS IN WOODLANDS. 107 



after month. The consequent weakened condition of the 

 trees would invite the bark beetles and other borers which 

 attack such trees, and, multiplying exceedingly, cut channels 

 beneath the bark until all the vital tissues are 

 destroyed. I have seen many trees defoliated 

 by the gipsy moth that afterward succumbed 

 to the attacks of these insidious borers, which 

 are probably the ultimate cause of the death Pig. 35. -De- 



„ 1 c T , 1 J structive bark 



of many defoliated trees. beetle, eaten 



The destruction of these larvae in their re- ^y ''''■*^- ^"^■ 



largea. 



treats under the bark is effected mainly by 

 insect parasites, predaceous insects, the various species of 

 Woodpeckers, and possibly by Titmice. The adult beetles, 

 when they emerge from their retreats in the spring, are also 

 attacked by many birds. The Woodpeckers are most valu- 

 able, because they drag from secret hiding places certain 

 boring coleopterous and lepidopterous larvae 

 that might otherwise destroy the trees. A 

 single borer may be sufficient to kill a young 

 tree, but the Woodpecker takes the perni- 

 cious grub from its burrow, and by eating 

 several at a meal may save many trees in 

 „. „„ ,„ ^ the course of a year. 



Fig. 36. — Wood- •' 



pecker hunting When the European leopard moth ap- 

 borers. peared in New York and Brooklyn, caus- 



ing great havoc among the trees in the parks, it was feared 

 that as the insect spread it would become a serious enemy 

 to the trees of the entire country ; but I was informed by 

 Dr. John B. Smith, entomologist to the New Jersey Agri- 

 cultural College Experiment Station, that this moth, while 

 a pest in cities, was doing little damage in the country, 

 where the native birds seemed to keep it in check. At 

 first it looked as if the large larvae, because of their habits, 

 would escape the birds. They are borers, beginning life 

 within the small twigs, and when these get too narrow for 

 them they eat their way out and crawl down outside to larger 

 twigs. It is then that they are taken by many native birds, 

 though the "English" Sparrows do not appear to check them. 

 Dr. Smith says that the Woodpeckers eat the female moths, 



