92 



THE BORERS OF OUR SHADE TREES. 



105. Poplar Tree Borer. 



jaws. As many as ninety eggs have been taken from a single 

 beetle. The grubs (Fig. 104, e ; a, enlarged view of the head 

 seen from above ; 5, the under view of the same : c, side view, 

 and d, two rings of the body enlarged), hatched from these 



eggs, undermine the bark to the 

 extent of six or eight inches, in 

 sinuous channels, or penetrate the 

 solid wood an equal distanc* It 

 is supposed that three years are 

 required to mature the insect. 

 Various expedients have been 

 tried to arrest their course, but 

 Avithout effect. A stream, thrown 

 into the tops of trees from the 

 hydrant, is often used with good 

 success to dislodge other insects ; 

 but the borer-beetles, when thus 

 disturbed, take wing and hover 

 over the trees till all is quiet, and 

 then alight and go to work again. The trunks and branches 

 of some of the trees have been washed over with various prep- 

 arations without benefit. Boring the trunk near the ground 

 and putting in 

 sulphur and 

 other drugs, and 

 plugging, have 

 been tried with 

 as little effect. 



The city of 

 Philadelphia has 

 suffered griev- 

 ously from this 

 borer. 



Dr. Swift re- 

 marks, in 1844, 

 that "the trees 

 in "Washington 

 and Indepen- 

 dence Squares 

 were first observed to have been attacked about seven years 

 ago. Within two years it has been found necessary to cut down 



lOG. Broad-necked Prionus. 



