382 REPORT OF THE COMMISSIONER OP AGRICULTURE. 



THE SUGAR-MAPLE BORER. 



(01 y cob his sjieciosas, Say.) 



This destructive borer, which has been described and figured in our 

 Bulletin on Forest Insects, is still at work in Maine, where we have 

 made such observations on its egg-laying habits and the mode of life of 

 the freshly-hatched larva, that it now seems possible to prevent its 

 entry into the heart- wood by cutting it out of the bark in the autumn. 



The burrows, or mines, either extend under the bark or descend into 

 the wood towards the heart of the tree. Different trees are variously at- 

 tacked. Where the worms remain under the bark large pieces are 

 loosened and gradually fall off, leaving sometimes nearly one side of 

 the trunk bare. At the same time the general health of the tree is im- 

 paired, as shown by the sparseness of the leaves. 



The beetles were unusually frequent in Brunswick during late July 

 and especially in August, and at this time lay their eggs. Although 

 none were found engaged in the operation, there is little doubt, as will 

 be seen below, that the process is nearly identical with that of the pine- 

 borer, or Monohammus. I found two mines of this borer which crossed 

 each other, though usually each follows an independent course, unless 

 much crowded. On a single tree from one side of which the bark had 

 fallen off in consequence of the attacks of this insect, there were about 

 twelve u mines," or burrows, of which ten ran up the trunk. The mines 

 were from 15 to 24 inches long, one measuring 2 feet and 8 inches in 

 length. At the upper end the mines are about f inch wide. The mine 

 either finally sinks deep in the wood or extends all the way under the 

 bark until at the extreme end, where it sinks in a little way to form a cell, 

 or chamber, for the chrysalis. 



The trees die slowly, and where the trunk has been mined on one side 

 only the tree lives on, though the foliage be much thinner. Trees may, 

 as we have observed, live for at least five or six years with a number of 

 borers in their trunks. 



Fresh from the observations made on the mode of egg-laying in the 

 common pine-borer, I looked, September 12, for the eggs or freshly- 

 hatched larvae of Glycobius spcciosus, and found the latter at once. The 

 Bev. Mr. Leonard, of Dublin, N. BL, many years ago, in a letter to Dr. 

 Harris, stated that the maple-tree borer, on hatching, remained in the 

 bark through the winter. Upon examining a sugar maple about 2 feet 

 in diameter, it was found that twenty eggs had been laid in dif- 

 ferent parts of the bark from near the ground to where the branches 

 originated, a distance of about 10 feet. The site of oviposition was 

 recognized by a rusty, irregular discoloration of the bark about the 

 size of a cent, and especially by the "frass," or castings, which to the 

 length of an inch or more were attached like a broken corkscrew to 

 the bark. On cutting into the bark, the recently-hatched larvae (5-7 mm 

 in length) were found lying in their mines, or burrows, at the depth of a 

 tenth to the sixth of an inch. 



The burrows already made were about an inch long, some a little 

 longer; the larva usually mines upward. No eggs were found, but 

 they are laid in obscurely marked gashes, about a fifth of an inch long, 

 usually near a crevice in the bark. 



These gashes and castings are readily discoverable, and it would be 

 easy to save these valuable shade trees by looking for them in the au- 

 tumn and winter or early spring and cutting out the worms. The bee- 



