540 
Fig. 1. Scurfy Scale. Purdue Bulletin 118. 
Control 
Same as for San Jose scale. 
E. O. Essie 
SEVENTEEN-YEAR Locust.—See Periodi- 
cal Cicada, this section. 
Srx-Spottrep Sprper.—See Red Spider, 
this section. 
SYNETA.—See Fruit Tree Leaf Syneta, 
this section. 
Tent Caterpillars 
Malacasoma erosa Stretch. 
Malacasoma pluvialis Dyar. 
Malacasoma constricta Stretch. 
By H. F. WItson 
Tent caterpillars, so-called because they 
build nests wherein they usually remain 
when not feeding. These nests are formed 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
out of silken threads secreted by the lar- 
vae and serve both as a shelter and a 
protection against natural enemies. 
Of the many different species which 
exist throughout the world only three are 
at all serious in the Northwest. To the 
casual observer there is little difference 
between the larvae and adults of these 
species when looked at separately. Taken 
side by side, however, the full-grown lar- 
vae may be easily distinguished, one 
species from the other. 
*According to Professor F. L. Wash- 
burn, a former entomologist of the Oregon 
Agricultural College, of the three, Malaca- 
soma erosa, Malacosoma pluvialis, and 
Malacasoma constricta, the first named 
feeds upon almost everything but the pear, 
viz.: apple, quince, cherry, rose, prune, etc. 
The second has about the same food plants 
as the first. The third devastates whole 
groves of oak, particularly Quercus gar- 
ryana, occasionally migrating to the 
prune, and thereby causing considerable 
alarm among orchardists. 
During the past two or three years M. 
pluvialis has been extremely abundant in 
the western part of Oregon, both on fruit 
and forest trees. Numerous reports have 
come in from about Portland and I have 
observed the larvae over many square 
miles of woodland in Southern Oregon. 
When these larvae are very numerous 
they can entirely strip a tree of its fo- 
liage in a very short time. When first 
hatched from the eggs they are not read- 
ily noticed, but as they grow larger they 
are readily distinguished both by their 
size and by the tents which they build. 
Toward the middle or latter part of the 
summer the larvae become full grown; 
they then seek crevices where they spin 
silken cocoons and change to pupae. After 
remaining in this stage a short time they 
change to the adult insects or moths 
which come forth and deposit the eggs. 
The eggs are deposited in masses on the 
small branches or shoots, and in the case 
of one species, where the eggs are laid 
on new shoots, the egg mass completely 
surrounds the twig. These are covered 
*P Sa>! 
periment Station, 
Washburn. Bulletin 33, Oregon Ex- 
1894. 
