Lambdina fiscellaria lugubrosa (Geometridae)

the western hemlock looper


Lambdina fiscellaria lugubrosa, the western hemlock looper, adult moth. Wings are narrow at the base with a banded pattern, 2 bands on forewing, 1 on rear wings. Distal edge of wings is angled. Light buff coloured.


Lambdina fiscellaria lugubrosa larva; note its typical Geometrid appearance with prolegs only on segments 6 and 10. "Looper," no prolegs except on segments 6 and 10. Broken dark lines on sides and 4 black dots on dorsum of each segment when mature. Length is 25 to 30 mm.

In August or September larvae drop to ground on "threads" and pupate in bark crevices or under debris. Moths emerge to lay eggs within 10 to 14 days.


Damage caused by feeding of Lambdina fiscellaria lugubrosa. Adults lay eggs on foliage. Eggs hatch the following spring. Early larval instars feed on new foliage. Later instars feed on older foliage and clip off small twigs. Injured foliage dries out and imparts the typical reddish colour of infestations.

Principal Hosts:

The preferred host is western hemlock, although Sitka spruce, Pacific silver fir, Douglas-fir and associated understory vegetation may be defoliated by this insect.

Economic Importance:

A very destructive defoliator that can be responsible for large losses of timber during the periodic outbreaks.

References and Links:

EAG: 486-487; FC: 205.

See HForest and JP17.

Additional Images:

severely defoliated western hemlock a western hemlock looper caterpillar early instar