|scientific name Tetracis cachexiata |
common name White Slant-line
Deciduous boreal forest and prairie riparian woodlands in Alberta.
Adults fly in mid to late June in Alberta.
A large cream white, nearly immaculate geometrid moth; the only wing markings consist of a straight, tan transverse line from the apex to the anal margin of the forewing. Hindwings unmarked.
The straight PM line and absence of other prominent wing markings will identify the two Tetracis species. T. cachexiata is much paler than T. crocallata, and lacks a discal spot and the dusting of dark scales found in crocallata.
The caterpillar is variably marked with tan, brown and black, bearing several small dorsal warts. The second thoracic segment is conspicuously thickened, giving the caterpillar a convincing "broken-twig" appearance (Wagner et al. 2001). Adults come to light, and pupae overwinter.
Not of concern.
Larvae are generalists on deciduous trees and shrubs (occasionally conifers in the East). Recorded hosts which occur in Alberta include alder (Alnus), birch (Betula), cherry (Prunus), poplar (Populus), Viburnum and willow (Salix) (Wagner et al. 2001).
Nova Scotia to central BC. In Alberta, occurs in the major river valleys of the prairies, and north to Athabasca and Fort McMurray. (McGuffin 1987). Although McGuffin (1987) reports this species from the central boreal region in Alberta, extensive surveying in recent years has failed to turn up T. cachexiata in the Boreal forest region in the province; all recent records are from the major river valleys of the southern prairies.
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