Butterflies and Moths of North America

collecting and sharing data about Lepidoptera

Sagebrush Girdle Moth
Plataea trilinearia (Packard, 1873)

Family: Geometridae
Subfamily: Ennominae
Identification: Forewings white, with gray or grayish brown scaling; basal area gray or grayish brown, extending outwardly along inner margin to middle of wing; maculation similar to that of personaria but with posterior, elliptical lobe of median area tending to be larger, and with t.p. line irregular in course, not inwardly dentate; median area outlined by prominent white band; discal dash white, elongate, prominent; subterminal and terminal areas concolorous; terminal line varying from absent to complete, narrow, dark brown; fringe white, brown opposite vein endings. Hind wings white, with variable number of pale grayish brown scales; maculation absent in most specimens, some with small discal dot and trace of dark subterminal area; terminal line as on forewings; fringe white, some specimens with small amount of brown scaling opposite veins.
Wing Span: 3.0-4.6 cm
Life History:
Flight: February to September in the south; May to August in the north (Alberta). They are most commonly seen (often in large numbers at lights) in spring.
Caterpillar Hosts: Larval foodplant apparently unknown but presumed to be wormwood (Artemisia sp.) - the same as that of a sister species Plataea personaria.
Adult Food:
Habitat: Varied, mostly arid and semiarid environments such as desert grasslands and mountians, sagebrush flats, short grasslands, and prairie badlands
Range: southeastern British Columbia to southwestern Saskatchewan, south to California and central Texas, and into Mexico
Management Needs:
Taxonomy Notes: None.