Scientific American Supplement, No. 803, May 23, 1891 | Page 8

gallons of water.
THE FOREST TENT CATERPILLAR.
Clisiocampa disstria (Hübner.)
This species, commonly known as the forest tent caterpillar, closely
resembles the apple tree tent caterpillar, but does not construct a visible
tent. It feeds on various species of forest trees, such as oak, ash, walnut,
hickory, etc., besides being very injurious to apple and other fruit trees.
The moth, Fig. 17, b, expands an inch and a half or more. The general
color is brownish yellow, and on the fore wings are two oblique brown
lines, the space between them being darker than the rest of the wing.
The eggs, Fig. 17, c and d, which are about one twenty fifth of an inch

long and one fortieth wide, are arranged, three or four hundred in a
cluster, around the twigs of the trees, Fig. 17, a. These clusters are
uniform in diameter and cut off squarely at the ends. The eggs are
white, and are firmly fastened to the twigs and to each other, by a
brown substance, like varnish, which dries, leaving the eggs with a
brownish covering.
[Illustration: FIG. 17.]
The eggs hatch about the time the buds burst, or before, and the young
caterpillars go for some time without food, but they are hardy and have
been known to live three weeks with nothing to eat, although the
weather was very cold.
[Illustration: FIG. 18.]
As soon as hatched they spin a silken thread wherever they go, and
when older wander about in search for food. The caterpillars are about
one and a half inches long when fully grown, Fig. 18. The general color
is pale blue, tinged with greenish low down on the sides, and
everywhere sprinkled with black dots or points, while along the middle
of the back is a row of white spots each side of which is an orange
yellow stripe, and a pale, cream yellow stripe below that. These stripes
and spots are margined with black. Each segment has two elevated
black points on the back, from each of which arise four or more coarse
black hairs. The back is clothed with whitish hairs, the head is dark
bluish freckled with black dots, and clothed with black and fox-colored
hairs, and the legs are black, clothed with whitish hairs.
At this stage the caterpillars may be seen wandering about on fences,
trees, and along the roads in search of a suitable place to spin their
cocoons, which are creamy white, and look very much like those of the
common tent caterpillar, except that they are more loosely constructed.
Within the cocoons, in two or three days they transform to pupæ of a
reddish brown color, densely clothed with short pale yellowish hairs.
The moths appear in two or three weeks, soon lay their eggs and then
die. The insects are not abundant many years in succession, as their

enemies, the parasites, increase and check them.
Many methods have been suggested for their destruction, but the most
available and economical are to remove the clusters of eggs whenever
found, and burn them, and to shower the trees with Paris green in the
proportion of one pound to one hundred and fifty gallons of water.
THE STALK BORER.
Gortyna nitela (Gruen.)
The perfect moth, Fig. 19, 1, expands from one to one and a half inches.
The fore wings are a mouse gray color, tinged with lilac and sprinkled
with fine yellow dots, and distinguished mainly by a white band
extending across the outer part. The moths hibernate in the perfect state,
and in April or May deposit their eggs singly on the outside of the plant
upon which the young are to feed. As soon as the eggs hatch, which is
in about a month, the young larvæ, or caterpillars, gnaw their way from
the outside into the pith.
[Illustration: FIG. 19.]
The plant does not show any sign of decay until the caterpillar is fully
grown, when it dies. The caterpillar, Fig. 19, 2, is about one and
one-fourth inches long, of a reddish brown color, with whitish stripes
along the body. The stripes on the sides are not continuous, and the
shading of the body varies, being darker on the anterior than on the
posterior portion. When fully grown, Fig. 20, the color is lighter and
the stripes are broader. At this stage of life it burrows into the ground
just beneath the surface, and changes into the pupa state. The pupa is
three-fourths of an inch long, and of a mahogany brown color. The
perfect moth appears about the first of September, and there is only one
brood in a season.
[Illustration: FIG. 20.]
The caterpillars feed in the stalks of corn, tomatoes, potatoes, dahlias,
asters, and also in young currant bushes, besides feeding on many

species of weeds. By a