Larval case "approximately 9-13 mm long. Silk of whitish grey, heavily covered by small pieces of plant fragments, usually by segments of grass stems, arranged longitudinally, often surpassing length of case, projecting in irregular fashion posteriorly." (Davis 1964)
See discussion here
for comparison to the most similar native species, Astala confederata
Introduced from Europe. First discovered in Boston in 1931. By 1964 the range extended from southeastern Canada to eastern Pennsylvania. BugGuide data
indicates it has expanded west to Illinois and Minnesota, with one apparent example in Washington state.
Chiefly "grasses, mosses, lichens, and other low plants"; occasionally scale insects. (Davis 1964)
1. Larval case. 2. Larva. 3. Pupa. 4. Adult female. 5. Adult male
Davis 1964 "Bagworm moths of the western hemisphere." Bulletin of the United States National Museum 244, 233 pages