Other Common Names
In Europe called Brown-tail Moth; I (TT) have followed Covell's spelling: Browntail Moth
Synonyms and other taxonomic changes
Euproctis chrysorrhoea (Linnaeus, 1758)
Nygmia phaeorrhea (Donovan, 1801)
Europe; accidentally introduced into Massachusetts in 1897. Now found in Maine, the Cape Cod area and eastern provinces of Canada (see remarks section, below).
Caterpillars feed on 26 genera of trees and shrubs belonging to 13 different families (Wikipedia). A major pest of hardwood forests.
Female lays her eggs in elongate oval masses from 12-18mm long on the undersides of leaves. These masses contain about 300 eggs and is covered with brown hairs from the female's abdomen. Young larvae feed gregariously, then tie 2 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. It forms a tough, grayish web from 2-6" long where they overwinter. Pupation occurs in silken cocoons spun among the leaves at the tips of twigs.(1)
Non-native, from Europe.
Within 20 years of its introduction into Massachusetts, browntail moth had spread to all New England states, parts of New York and the Canadian Maritime Provinces. However populations soon receded and by the 1960's, the browntail moth was limited to Cape Cod and a few islands off the Maine coast in Casco Bay. Browntail moth populations are again building in Maine and caterpillars can be found along the coast and inland about 60 miles from the western Maine border to the New Brunswick border. In 2020, the greatest concentrations were seen in mid-coastal Maine and the capitol region. The browntail moth is also still known from the Cape Cod region in Massachussets and moths have been captured in far northern and western Maine as well as in eastern Canadian provinces. (Allison Kanoti, Maine Forest Service)
CAUTION: The caterpillar's hairs are extremely dangerous. They break off as barbs and upon contact with skin can cause rashes, skin irritation, headaches and breathing difficulties.