Page 288 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

MOTH CATERPILLARS

FAMILY Psychidae
DISTRIBUTION Eastern United States, west to New Mexico, and south to
the Caribbean
HABITAT Forests and also urban trees
HOST PLANTS At least 50 families of deciduous and evergreen trees and shrubs,
including juniper and cedar (Juniperus spp.), oak (Quercus spp.),
willow (Salix spp.), maple (Acer spp.), and pine (Pinus spp.)
NOTE Caterpillar that lives inside a silk bag decorated with vegetation
CONSERVATION STATUS Not evaluated, but common

ADULT WINGSPAN
¾–1 ⁄ in (20–30 mm)
CATERPILLAR LENGTH

⁄ –1¼ in (24–32 mm)
THYRIDOPTERYX EPHEMERAEFORMIS
EVERGREEN BAGWORM
286
(HAWORTH, 1803)

Evergreen Bagworm caterpillars hatch from eggs laid by
the wingless adult female in the bag that she, as a caterpillar,
constructed. The young larvae are dispersed through the air,

attached to silk threads—the only e ective method of dispersal
over greater distances. Once they land and start feeding on the
Actual size
new host, the caterpillars construct their own silk bags around
themselves, continuing to enlarge them and attaching fragments
of foliage throughout their growth. Excrement is expelled from

The Evergreen Bagworm caterpillar has a a hole in the bag’s lower end. Female caterpillars gradually
pigmented and sclerotized head. Its front end, ascend to the crown of a tree, while males stay at the same level
only ever visible as it feeds, partially emerging
from the bag’s turtleneck opening, is usually throughout their development.
white or beige with extensive black markings.
Past the abdomen, the larva is a nondescript
black brown. The bag’s appearance varies The larvae develop through seven instars over about three
according to the host plant.
months, then pupate in the bag. When the adults eclose, only
the winged males start flying—looking for bags containing
wingless females. The male mates by inserting his abdomen
into the lower opening of the female bag. The fertilized
female then lays a large number of eggs inside her bag,
where the eggs spend the winter.