An annotated list of the Lepidoptera of Alberta, Canada Pohl, Greg Anweiler, Gary Schmidt, Christian Kondla, Norbert ZooKeys 2010 2010-03-05 38 38 1 549 6247J 82593 Leach 1815 [184,352,483,510] Insecta Geometridae Animalia Lepidoptera 194 195 Arthropoda family  Primarily medium-sized (but ranging from 10 to 60 mmwingspan) moths with relatively slender bodies and broad, butterfly-like wings. The group is united by the unique structure of the abdominal tympanal organs and by the form of the larvae, which have only two pairs of abdominal prolegs, with the exception of a few species that lack this character. Th e moths in this family are commonly called loopers or inchworms for their larval crawling habit. Although some adults are brightly or boldly colored, most exhibit subtle patterns with browns and grays, often cryptically colored to match bark or leaves. Many geometrids rest with the fore- and hindwing to the side and appressed to the resting surface, exhibiting a continuation of pattern and color between fore- and hindwings. The larvae of most species feed on trees and shrubs, both deciduous and coniferous. Given their diversity, abundance, degree of host specialization, and broad distribution, members of the Geometridaerepresent a significant component of most forest insect communities. The family Geometridaeis one of the three largest lepidopteran families, encompassing about 21 000 described species, primarily in the tropics. About 1400 species of Geometridaeoccur in North America, 293 of which are reported from AB. Relationships at the subfamily level have been reassessed recently; Young (2006)showed that the subfamily Larentiinaeis almost certainly basal within the Geometridaeand that Ennominaeas currently defined is not monophyletic (see also Abraham et al. 2001). The subfamily Sterrhinaeis placed as the second-most basal group. Th e order in which the Geometridaesubfamilies are presented here follows these new findings.