INJURIOUS INSECTS OF I909 AND IQIO. 105 
girdle a tree in this way, and hosts of elms in Minnesota have thus 
been killed. Frequently exudations, sometimes in the form of gum, 
and more or less of sawdust-like castings, will mark on the surface 
of the bark the opening of a burrow. This exuding matter from 
the burrow appears to attract ants; and we have sometimes detected 
the presence of this borer in an elm by first noticing the ants as- 
cending its trunk. The deadly work of this insect begins to show 
itself in midsummer, though a tree-owner might not realize the 
fatal character of the attack until the following spring; when, per- 
haps, by the branches not leafing out properly, and by the generally 
diseased appearance of an affected tree, one realizes that something 
very serious ts the matter. The branches die, sometimes even in 
the fall following the attack, and it is only a question of time— 
short at that—when the tree, which has taken so long to grow, 
succumbs to the work of an insect hardly more than an inch long. 
We found in Minneapolis, on April 2oth, toro, trees dying from the 
previous summer’s attack, and containing at that date larvae of this 
beetle, of various ages, and pupae almost ready to emerge; indicat- 
ing that the adult beetles would begin to emerge very shortly, pos- 
sibly by May tst or earlier, and continue to emerge during the sum- 
mer, mating and laying their eggs on neighboring elms possibly 
not hitherto affected; dooming them, also, to a premature death. 
These facts are significant; for, when one finds trees evidently be- 
yond cure, on account of the work of this borer, radical treatment 
is demanded. Such trees should be cut down in winter or very 
early spring, and not piled up for firewood, thus allowing the bee- 
tles to mature and carry on their destructive work, but burned, 
trunk and branches at once, destroying all the beetles therein in 
whatever stage they may occur. This should be done by park 
boards or other authorized officials, since individual owners are 
apt to neglect this important measure, thus allowing the pest to 
spread to the trees of their neighbors. Trees cut down in the late 
fall or early winter, might safely be used for firewood during that 
winter, but should be all burned before April Ist. 
