Glaucopsyche lygdamus, the silvery blue, is a small butterfly native to North America. Its upperside is a light blue in males and a dull grayish blue in females. The underside is gray with a single row of round spots of differing sizes depending upon the region. G. lygdamus is found over much of the western United States and most of Canada extending north excepting most of Nunavut and the high Arctic islands. Wingspan is from 18 to 28 mm. It occurs in a variety of habitats including alpine meadows, shale barrens, dunes, and wooded areas. It feeds on Lupinus plants.

- Eastern tailed-blue (Cupido comyntas) has small 'tails' on hindwings - Western tailed-blue (Cupido amyntula) has small 'tails' on hindwings - Arrowhead blue (Glaucopsyche piasus) - Greenish blue (Aricia saepiolus) has two rows of small black spots on the underside of both wings - Boisduval's blue (Aricia icarioides) has two rows of small black spots on the underside of both wings