Winter is spent in the egg stage, and hatching occurs about the time the buds of 
the host tree begin to unfold in the spring. In Florida, adults may appear and lay 
their eggs even before hatching occurs in the northern parts of the insect’s range. 
The larvae are gregarious. As soon as they hatch, they begin the construction of a 
tent in a nearby trunk or branch crotch, and continue to enlarge the tent as they 
grow. From this tent, the larvae crawl out to the foliage to feed. After feeding, they 
return to the tent to rest. When they become full grown, they leave the nest and 
wander in search of places to pupate. Pupation occurs in tough silken cocoons, 
dusted with a yellowish powder, on the bark of trees, on fences, on brush and 
weeds, among dead leaves and other debris on the ground, and even on the sides of 
buildings. When the adults appear, they lay eggs in essentially a clasping mass on 
small twigs or branches, or on the trunks of small trees. In the Lake States, eggs are 
often found on the trunks of very small trees about 15 cm above the ground. There 
is One generation per year (/56, 302). 
Most of the hosts of the eastern tent caterpillar have little value, thus it usually 
does not cause economic losses. It may be of some importance, however, when it 
defoliates commercial-size black cherry whose wood is of value for furniture (700). 
The species is primarily a nuisance pest. Infested trees in parks, recreational areas, 
along roadsides, and in the vicinity of homes may be disfigured. 
During most years, the eastern tent caterpillar is controlled satisfactorily by its 
natural enemies. Egg parasites may account for one-quarter of the exposed eggs, 
but only | percent of the spumaline-covered eggs (276). Periodically, however, 
populations reach outbreak proportions. An effective method of control on isolated 
trees is to prune off and burn twigs containing egg masses. Destroying larval tents, 
preferably when the tents are still small, is also effective. Bacillus thuringiensis and 
a number of chemical insecticides are effective in controlling the larvae. 
Malacosoma californicum lutescens (Neumoegen & Dyar), the prairie tent 
caterpillar, occurs throughout the Great Plains area east of the Rocky Mountains to 
central Texas. Its hosts are recorded as common chokecherry, willow, American 
plum, and gooseberry. Male adults range from dark reddish-brown to very light 
yellow; females are yellowish to medium reddish-orange brown. The forewings are 
crossed by light yellowish lines, and the wingspread is about 37 to 50 mm. Full- 
grown larvae are about 50 mm long. The head is blue, mottled with black, and 
sparsely covered with fine whitish to orange setae. The middorsal area of each 
abdominal segment is marked with an elongate somewhat pointed, blue-white dash. 
These dashes combine to form a broken middorsal stripe. 
Eggs are laid in flattish, clasping masses on twigs and branches and are covered 
with light-brown or grayish spumaline. The larvae construct relatively large tents 
that look like those of the eastern tent caterpillar. Defoliation is usually confined to 
branches, but during outbreaks trees may be completely defoliated. Because of the 
low value of its hosts, the species is of minor economic importance. 
The Sonoran tent caterpillar, M. tigris (Dyar), occurs in the southern Great 
Plains, southern Rocky Mountains, the Southwest, and Mexico. So far, it is not 
known to occur farther eastward than central Texas. Its host plants are various oaks 
and possibly other species. Eggs are laid in encircling bands on very small twigs, 
occasionally dead twigs. The masses differ from those of other members of the 
genus in not being covered with spumaline. The larvae construct relatively small 
tents on which they congregate to molt. Tents are usually formed near the end of 
each instar. This species does not appear to be of much economic importance, 
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