APPLE PESTS 
Unicorn Prominent 
Schizura unicornis 
During August and September, a sin- 
gular caterpillar is occasionally found 
feeding on apple foliage. It is reddish 
brown, variegated with white on the back, 
and has a green patch on each side, ex- 
tending over the second and-.third seg- 
ments, while from the top of the fourth a 
conspicuous horn is projected. It eats out 
a notch from the edge of the leaf and 
then fits itself to the notch, clasping the 
eaten edge of the leaf with its prolegs 
while the prominent horn is made to ex- 
tend over a portion of the vacant space 
where belonged the devoured tissue. The 
outline of the back, thus simulating the 
irregular edge of the leaf, enables the cat- 
erpillar to elude the sight of all but the 
most searching eyes. This caterpillar is 
known as the unicorn prominent, and 
though interesting, rarely, if ever, be- 
comes sufficiently numerous to be troub- 
lesome. It reaches full size in Septem- 
ber and descends to the ground, where a 
cocoon is constructed under the fallen 
leaves and trash. The light-brown moth 
does not appear until the following sum- 
mer. No measures against this insect 
are needed under ordinary circumstances. 
If a midsummer spraying with arsenate 
of lead is made in July or August, these 
caterpillars are apt to be thinned down 
until they attract no notice. 
H. A. GossaARp, 
Wooster, Ohio. 
WEEvIL.—See Bronze Apple Tree Wee- 
vil, this section. 
Western Tussock Moth 
Hemerocampa vetusta Boisd. 
H. F. WILson 
The distribution of this insect in the 
United States is at present limited to the 
Pacific coast, and on account of the sim- 
ilarity of its work to that of the tent 
caterpillars, is often taken for one of 
those insects. The two are quite differ- 
ent, however, in appearance, both in the 
larval and adult stages. 
The eggs begin to hatch about the time 
the leaves are spreading out in the spring, 
and at that time the young larvae are 
almost black. For a few days they re- 
543 
Hig. 4. 
Western or California Tussock Moth. 
(a) and (b) Adult wingless females. (d) 
Cocoons. (e) Egg masses attached to the 
cocoons. (f) Eggs. (g) Internal parasite 
working upon cocoons. (Hssig.) 
main clustered about the egg mass and 
apparently feed on the substance which 
covers and holds the latter together. 
After the larvae have all hatched and 
have broken out from the eggs, the egg 
mass will appear as if riddled with holes. 
The larvae cut these in escaping from the 
eggs. : 
After a few days the larvae spread on 
to the nearby buds and leaves. At first 
the damage is very slight and consists of 
minute holes in leaves, blossoms and fruit. 
Later they feed entirely on the leaves 
which they devour, leaving only portions 
of leaves and the larger veins. 
Unlike the larvae of the tent caterpil- 
lars, they spread out over the tree and 
do not collect at night nor do they build 
nests or tents. They are somewhat wan- 
dering in their habits and oftentimes can 
be seen crawling about on the ground, go- 
ing from one tree to another. 
The original description of the larvae 
is given as follows: “Ground color vel- 
vety black. Head black, rather shining, 
with yellow line in front. From the sec- 
ond segment springs two bundles of long 
black hairs. The space between these is 
bright vermilion red; at the base of each 
