ware 
A courtesy of Ziegler; B, C, and D courtesy o 
Shrdder; Landwirtschaftskammer, Rheinland. 
Figure 103.—The browntail moth, Euproctis 
chrysorrhoea: A, female ovipositing; B, egg mass on 
leaves; C, larvae; D, silken cocoons opened to show 
pupae. 
Browntail moth adults are pure white except for the tip of the abdomen, which is 
covered with brown hairs. The female is rather heavy-bodied and has a wingspread 
of about 37 mm. Males are more slender and somewhat smaller. Full-grown larvae 
are about 37 mm long. The head is light brown; the body is dark brown to almost 
black with a broken white line on either side and two conspicuous red spots near the 
posterior end. There are also numerous tubercles with long, barbed hairs and many 
short, brown hairs on the dorsum and sides. These urticating hairs are allergenic to 
humans and cause a severe rash when they come in contact with skin. 
Adults appear in early July, and the female deposits her eggs in elongate oval 
masses from 12 to 18 mm long on the undersides of leaves. Each mass contains 
about 300 eggs and is covered with brown hairs from the female’s abdomen. Young 
larvae feed gregariously on the surface of the leaves. Later, they tie two or more 
leaves together with silk near the tip of a branch. Then they spin a web over the 
outside of these leaves and fasten them securely to the twig, thereby forming a 
tough, grayish web from 5 to 15 cm long where they spend the winter. Feeding 1s 
resumed in the spring, and the larvae become full grown by mid-June. Pupation 
occurs in silken cocoons spun usually among the leaves at the tips of twigs. 
The browntail moth, although one of the better known forest and shade tree 
insects in the Eastern United States, is no longer of economic importance. For some 
undetermined reason, it has almost disappeared. Introduced parasites, many of 
which became established (328), and a fungus disease probably helped toward its 
control, but it seems unlikely that they were primarily responsible for its decline. 
235 
