Adult: stout-bodied; forewing light brown with two darker, thin parallel lines extending across mid-portion, the area between often being dark and appearing as a single broad, dark band
Larvae: dark-gray to brownish-black background body color, highlighted by broad, pale-blue lines and thin, broken yellow lines extending along each side; dorsum of each abdominal segment has distinct whitish keyhole or shoeprint-shaped marking; body has fine, whitish, and sparsely distributed hairs
throughout most of United States and southern Canada but more common east of Mississippi River
on or near host tree species
Adults usually fly from April to July (as early as February in Florida). Caterpillars typically April-June.
larvae feed on leaves of alder, basswood, birch, cherry, oak, poplar, willow
One generation per year; larvae spin silken mats on tree trunks and large branches where they congregate to molt or rest from feeding; larvae also deposit silk in strands along which they travel to and from feeding sites; overwinters as larva in masses surrounding tree branches. (Unlike Eastern Tent Caterpillar, this species does not form silken tents.)
Eastern Tent Caterpillar
) has an unbroken cream/white line along its back, and a dark face.
The adult Malacosoma americanum have light colored transverse lines
Covell, p. 54, plate 11#3 (1)
Wagner, p. 22--photo of caterpillar (2)
Wagner, p. 227--photo of caterpillar, specimen of adult (3)
Moth Photographers Group
- range map, photos of living and pinned adults.
live adult images
(Lynn Scott, Ontario)
live larva images
plus description and other info (U. of British Columbia)
pinned adult images
showing variation among males, and example of female (James Adams, Dalton State College, Georgia)