The caterpillars are fairly nondescript making field identification difficult. Identification is best achieved using keys which rely on the arrangement of hairs. The adult moths are night-flying. Geometridae - the inchworms or loopers. This family is second to the noctuids in containing the most species of Lepidoptera in the Pacific Northwest.
Most species feed either on conifers or broadleaf plants, few on herbs and grasses.
Full grown caterpillars in small species may be only 20 mm while large species may be 70-80 mm long. For most of the species the adult moths are night-flying. Hesperiidae - the caterpillars of skippers. External leaf feeders but may be found within tied leaves, occurring primarily on broadleaf plants, including many species associated with grasses. The most diagnostic trait for identification is that the first segment of the thorax is constricted.