378 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



this insect, there were about twelve "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 three-quarters of an inch wide. The mine either finally sinks 

 deep ill 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 tree dies slowly, and where the trunk has been mined on one 

 side only the tree livess 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 larvtie of Olycobius speciosus, and found the latter at once. The 

 Rev. Mr. Leonard, of Dublin, N. H., 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 two 

 feet in diameter, I found that twenty eggs had been laid in difl^erent 

 parts of the bark from near the ground to where the branches origi- 

 nated, a distance of about 10 feet. The site of oviposition was recog- 

 nized by a rusty, irregular discoloration of the bark about the size of a 

 <;ent, 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 to 7™™ in 

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

 tenth to a sixth of an inch. 



The burrows already made (Fig. 140) 

 were about an inch long, some a little 

 longer ; the larva usually mines upward. 

 ifo 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 look- 

 ing for them in the autumn and winter 

 or early spring, and cutting out the 

 worms. The beetles were not uncom- 

 mon at Brunswick in July and August 

 in 1884. Of six grubs which I cut out 

 over half seemed unhealthy, perhaps 

 diseased by the water which had pene- 

 trated their mines. 



I have recommended protecting val- 

 uable shade trees by wrapping the 

 trunks with narrow bands of cloth well saturated with kerosene oil in 



Fig. 140. — Mines of recently hatched larvae 

 of Olycobius speciosus. 



