w, and _d_, two rings of
the body enlarged), hatched from these eggs, undermine the bark to the
extent of six or eight inches, in sinuous channels, or penetrate the
solid wood an equal distance. It is supposed that three years are
required to mature the insect. Various expedients have been tried to
arrest their course, but without effect. A stream, thrown into the tops
of trees from the hydrant, is often used with good success to dislodge
other insects; but the borer-beetles, when thus disturbed, take wing and
hover over the trees till all is quiet, and then alight and go to work
again. The trunks and branches of some of the trees have been washed
over with various preparations without benefit. Boring the trunk near
the ground and putting in sulphur and other drugs, and plugging, have
been tried with as little effect.

[Illustration: 105. Poplar Tree Borer.]

The city of Philadelphia has suffered grievously from this borer.

[Illustration: 106. Broad-necked Prionus.]

Dr. Swift remarks, in 1844, that "the trees in Washington and
Independence Squares were first observed to have been attacked about
seven years ago. Within two years it has been found necessary to cut
down forty-seven European lindens in the former square alone, where
there now remain only a few American lindens, and these a good deal
eaten." In New England this beetle should be looked for during the first
half of June.

[Illustration: 107. Larva of the Plain Saperda.]

The Poplar tree is infested by an other species of Saperda (S.
calcarata). This is a much larger beetle than those above mentioned,
being an inch or a little more in length. It is grey, irregularly
striped, with ochre, and the wing-covers end in a sharp point. The grub
(Fig. 105 _a_; _b_, top view of the head; _e_, under side) is about two
inches long and whitish yellow. It has, with that of the Broad-necked
Prionus (P. laticollis of Drury, Fig. 106, adult and pupa), as Harris
states, "almost entirely destroyed the Lombardy poplar in this vicinity"
(Boston). It bores in the trunks, and the beetle flies by night in
August and September. We also figure the larva of another borer (Fig.
107 _c_; _a_, top view of the head; _b_, under side; _e_, dorsal view of
an abdominal segment; _d_, end of the body, showing its peculiar form),
the Saperda inornata of Say, the beetle of which is black, with ash gray
hairs, and without spines on the wing-covers. It is much smaller than
any of the foregoin