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Western false hemlock looper

Western false hemlock looper - Dorso-lateral view of mature larva, on Douglas-fir
  • Latin name: Nepytia freemani (Munroe)
  • French name: Arpenteuse de Freeman
  • Order: Lepidoptera
  • Family: Geometridae


British Columbia, United States



Damage, symptoms and biology

Western false hemlock looper is a common and occasionally destructive solitary defoliator.

Mature larva to 25 mm long. Head, tan with black spots. Dorsum tan with rust coloured suffusion; subdorsal stripe creamy yellow, edged with fine dark lines; supraspiracular stripe tan containing a fine wavy dark line; spiracular stripe broad, yellow and edged with fine dark lines. Tan areas replaced by green in prepupal larvae.

This species overwinters in the egg stage. Larvae emerge in late May and initially feed on the new growth. Later in the season as the current-year's foliage is depleted, the larvae move toward the bole and consume older foliage. The larvae are wasteful feeders, often consuming only parts of needles and chewing them off at their bases; the accumulation of partially consumed needles causes heavily infested trees to appear scorched. Pupation occurs on twigs or on the foliage in late July or August and adults emerge from August to October. Females lay an average of 70 eggs singly or in small clusters on both sides of the host needles.

Life cycle (West of the Rockies)

Life cycle (West of the Rockies)
Stage/Month J F M A M J J A S O N D

Canadian Forest Service Publications

Western false hemlock looper

Diet and feeding behaviour

  • Phyllophagous : Feeds on the leaves of plants.
    • Free-living defoliator: Feeds on and moves about freely on foliage.
Information on host(s)

Main host(s)

Engelmann spruce, ponderosa pine, Rocky Mountain Douglas-fir, subalpine fir, western hemlock


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