e the other members of the (_Lytta_)
family, it lives under ground while in the larva state, and is
troublesome only when in the perfect or winged state.

~The Black-Rat Blister-Beetle~, (_Lytta murina_, Le Conte.)--This species
(Fig. 8,) is entirely black. There is a very similar species, the black
blister-beetle, (_Lytta atrata_, Fabr.,) from which the black-rat
blister-beetle is distinguishable only by having four raised lines
placed lengthwise upon each wing-case, and by the two first joints of
the antennae being greatly dilated and lengthened in the males, of the
lath species. It is asserted by some authors that the black
blister-beetle is injurious to the potato; but I can not see how it
could do much damage to that crop, as the perfect insect does not appear
until late in August, when the potato crop is nearly out of its reach.
Not so, however, with the black-rat blister-beetle, which is on hand
ready for business early in the season. This insect does considerable
damage to the potato in Iowa, and neighboring States; it is also found,
though in not so great numbers, throughout the whole of the Northern
States.

~The Margined Blister-Beetle~, (_Lytta marginata_, Fabr.)--This species
(Fig. 9) maybe at once recognized by its general black color, and the
ash-gray edging to its wing-cases. It usually feeds on certain wild
plants, but does not object to a diet of potato-leaves. Though found
over a large extent of country, it seldom appears in numbers large
enough to damage the potato crop materially. Like other blister-beetles,
it goes under ground to pass into the pupa state, and attacks the potato
only when it is in the perfect or winged state.

~The Three-Lined Leaf-Beetle~, (_Lema trilineata_, Olivier.) The larva of
the three-lined leaf-beetle may be distinguished from all other insects
which prey upon the potato by its habit of covering itself with its own
excrement. In Figure 10, _a_, this larva is shown in profile, both full
and half grown, covered with the soft, greenish excrementitious matter
which from time to time it discharges. Figure 10, _c_, gives a somewhat
magnified view of the pupa, and Figure 10, _b_, shows the last few
joints of the abdomen of the larva, magnified and viewed from above. The
vent of the larva, as will be seen from this last figure, is situated on
the upper surface of the last joint, so that its excrement naturally
falls upon its back, and by successive discharges is crowded fo