IN T SECT INJURIES TO SHADE TREES. 337 



(c) Borers. 



Maple Borer. Plagionotus speciosus, Say. 



Maple trees in New Haven are more seriously injured by the 

 maple borer than by any other species of insect. 



The adult is a beautiful black beetle about an inch long, 

 ornamented with cross-bands of bright yellow. The eggs are 

 laid on the trunks of the maples in July and August and the 

 young borers, as soon as hatched, tunnel in the bark or wood, 

 where they remain through the winter. The appearance of 

 these beetles is shown in figure 7, Plate XL Usually the main 

 tunnel is between the wood and bark, and sometimes passes 

 nearly around the trunk in a spiral and upward course, girdling 

 it. Examples of the injuries are shown in Plate XI, figure 

 10 and Plate XII, figure n. The "sawdust" or castings are 

 thrown outside the burrow and serve as a guide to trees which 

 have been attacked. The burrows often run deep into the solid 

 wood and the larva doubtless passes the winter in these more 

 protected chambers. 



The life-history of this borer is not fully known, but it is 

 supposed that two years are required for its full development. 



Elm Borer. Saperda tridentata, Oliv. 



This enemy of the elm often causes great injury before its 

 presence is suspected, and makes numerous galleries in the 

 inner bark, so that the bark will sometimes separate from the 

 wood in large sheets. The beetle is about half an inch in length, 

 slate-colored, with orange markings. Its appearance is shown 

 in figure 8, and the characteristic injuries caused by it in figure 

 9 of Plate XL 



The Pigeon Tremex. Tremex columba, L. 



Injured and dying elms are often attacked by this and many 

 other species, which seldom attack healthy trees. 



The Leopard Moth. Zeuzera pyrina, Fabr., is exceedingly 

 injurious to elms and maples about New York City. The 

 adult is a large white moth, spotted with black, and the larva 

 makes deep burrows into the wood. 



7. Lack of Knowledge and Care in Planting. 

 The statements in the preceding pages have mainly to do 

 with the life and health of the trees. A further consideration, 

 which is of great importance and which is often overlooked, is 



