380 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 
hovered around them. For fifteen years or more some large button- 
wood trees in Cambridge have been visited by them in the same way." 
Prof, J. A. Limner, State Entomologist of New York, has communi- 
cated the following facts to the Country Gentleman: 
Something has attacked a large maple tree iu front of my house. The trunk looks 
M it a large dose of buckshot had been shot into it, having fifty or more clean holes 
about one-eighth of an inch across. Can you tell me what to do to save the tree? 
I have seen a large insect like a wasp, with several boring arrangements at least 
'3 inches long each, inserting these into the tree. Do these cause the mischief? 
W. S. J. 
l'ou<jhkeep8ie, X. V. 
I Answer by Prof. J. A. Lintner, State Entomologist] 
Theseveral holes iu the maples have been bored by the larva? of Tremex columba, 
one of our saw-flies and the largest of our species. The female is armed with a stout 
borer, the end of which is furnished with teeth, by means of which it is thrust 
through the bark into the wood, to the depth sometimes of half an inch and the egg 
inserted. Occasionally the female is unable to withdraw her borer, when she may 
be captured, during the mouths of July and August, struggling to escape from the 
tree. The larva hatching from the egg burrows into the trunk, and when it has 
nearly matured, by the aid of its strong jaws, it enlarges its round burrow outwardly 
to the size often of a small lead pencil, to permit the escape of the perfect insect. 
While maples are more frequently attacked by this insect than other trees, it is 
also found in oaks, elms, aud sycamores, and more commonly in those planted as 
shade trees in streets or about dwellings. Unless it is very abundant it does not 
destroy the tree that it attacks, but the holes soon heal over without serious injury 
following. Its injuries are far less serious than are those of another borer of the maple, 
the Glycobius speciosus (Say), a beautiful long- horned beetle, the black wing-covers 
of which are prettily ornamented by a yellow W, au( i D Y other yellow bands and 
spots. 
" The female, when about to lay her eggs, draws her borer out of its 
sheath, till it stands perpendicularly under the middle of her body, 
when she plunges it, by repeated wriggling motions, through the bark 
into the wood. When the hole is made deep enough, she then drops 
an egg therein, conducting it to the place by means of the two furrowed 
pieces of the sheath. The borer often pierces the bark and wood to 
the depth of half an inch or more, and is sometimes driven in so tightly 
that the insect cannot draw it out again, but remains fastened to the 
tree till she dies. The eggs are oblong-oval, pointed at each end, and 
rather less than one-twentieth of an inch in length." Harris adds, what 
has been observed frequently by others since his time, that these larva 
are often destroyed by the maggots or larvae of two singular ichueu- 
mon flies (Rhyssa at rata and lunator). These are the largest known 
ichneumon flies ; they are provided with long, slender borers or ovi- 
positors from 3 to 4 inches iu length, which they thrust into the 
deep holes made by the Tremex borers, in the bodies of which they 
insert an egg. 
(We have, however, observed one of these Rhyssa? engaged in 
ovipositing in an elm tree infested with the larvse of Compsidea 
tridcntata.) 
