Fifth report of the United States Entomological Commission, being a revised and enlarged edition of Bulletin no7, on insects injurious to forest and shade trees . h ofan inch or more were attached like a broken corkscrew to the cutting into the bark, the recently-hatched larvae (5 to 7™ inlength) were found lying in their mines, or burrows, at the depth of atenth to a sixth of an inch. The burrows already made (Fig. 140)were about an inch long, some a littlelonger; the larva usually mines eggs were found, but they are laidin obscurely marked gashes, about afifth of an inch lo
Fifth report of the United States Entomological Commission, being a revised and enlarged edition of Bulletin no7, on insects injurious to forest and shade trees . h ofan inch or more were attached like a broken corkscrew to the cutting into the bark, the recently-hatched larvae (5 to 7™ inlength) were found lying in their mines, or burrows, at the depth of atenth to a sixth of an inch. The burrows already made (Fig. 140)were about an inch long, some a littlelonger; the larva usually mines eggs were found, but they are laidin obscurely marked gashes, about afifth of an inch long, usually near acrevice in the bark. These gashes and castings are readilydiscoverable, and it would be easy tosave these valuable shade trees by look-ing for them in the autumn and winteror early spring, and cutting out theworms. The beetles were not uncom-mon at Brunswick in July and Augustin 1884. Of six grubs which I cut outover half seemed unhealthy, perhapsdiseased by the water which had pene-trated their mines. I have recommended protecting val-uable shade trees by wrapping thetrunks with narrow bands of cloth well saturated with kerosene oil in. Fig. 140.—Mines of recently hatched larvaeof Olycobius speciosus. MAPLE BORERS. 379 August and September, so as to drive off the beetles and to destroy thefreshly-hatched grubs, but since discovering how easily the grubs andcastings of the freshly-hatched worms can be detected a few days orweeks after the eggs have been laid, it seems obvious that the easiestand surest preventive is to cut out the grubs when lying in theirautumn and winter quarters just under the surface of the bark. It isalmost impossible to destroy the fully-grown worms in their minesor burrows, since the latter extend up the tree either directly under thebark or are sunken in the wood. On one tree nearly destroyed by thisborer, out of about fourteen mines twelve extended upward. Hence itis useless to try to find the hole and inject oil into it. There no
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