Adult butterflies typically begin emerging in early August and may be observed until mid- or late-September. Females lay eggs throughout the adult flight period. This butterfly produces only one brood per year. Females lay eggs singly and in small clusters on larval host plants in late summer. The leaves of the larval host plant provide both food and shelter throughout the larval instar phases. All life stages of Lange’s metalmark are closely tied to a variety of naked-stemmed buckwheat (Eriogonum nudum var. psychicola), which is the primary nectar source for adults, as oviposition sites, and as the larval food plant.

Lange's metalmark butterfly is a small metalmark butterfly. The wingspan is roughly 25 mm.

Lange’s metalmark butterflies have brown and orange coloring on the wings with white markings. The hindwing pattern is characterized by a gray-brown pattern beneath, which can make the butterfly very difficult to see when resting with its wings up in buckwheat foliage. The Lange’s metalmark butterflies is the only metalmark butterfly that occurs at Antioch Dunes, and subtle differences in wing coloration differentiate it from other Mormon metalmark subspecies. Caterpillars are purple and black.

Male and female Lange's metalmark butterflies reproduce during the late summer flight period. Males search for females and then mating takes place, usually on plant material. Males and females can stay coupled for a relatively long time (e.g., 2 hours), and are almost motionless during this time. Females lay fertilized eggs within a few days of mating. 

Adult butterflies typically begin emerging in early August and may be observed until mid- or late September. Females lay eggs throughout the adult flight period. This butterfly produces only one brood per year. Females lay eggs singly and in small clusters on the larval host plant in late summer. The eggs remain dormant until the first part of the rainy season, which usually occurs in the fall, at which time larvae hatch and then crawl to the base of buckwheat plants where they overwinter and feed on the foliage of buckwheat plants. The larvae have been observed feeding at night and have also been observed during daytime. Pupation occurs in mid-summer in the litter at the base of buckwheat plants. The leaves of the larval host plant provide food and shelter throughout the larval instar phases. All life stages of Lange’s metalmark are closely tied to a variety of naked-stemmed buckwheat (Eriogonum nudum var. psychicola), which is the primary nectar source for adults, is used to lay eggs and as a larval food plant.

Adult butterflies typically begin emerging in early August and may be observed until mid- or late September. Females lay eggs throughout the adult flight period. This butterfly produces only one brood per year. Females lay eggs singly and in small clusters on the larval host plant in late summer. The eggs remain dormant until the first part of the rainy season, which usually occurs in the fall, at which time larvae hatch and then crawl to the base of buckwheat plants where they overwinter and feed on the foliage of buckwheat plants. The larvae have been observed feeding at night and have also been observed during daytime. Pupation occurs in mid-summer in the litter at the base of buckwheat plants. The leaves of the larval host plant provide food and shelter throughout the larval instar phases. All life stages of the Lange’s metalmark are closely tied to a variety of naked-stemmed buckwheat (Eriogonum nudum var. psychicola), which is the primary nectar source for adults, is used to lay eggs and as a larval food plant.

The Lange’s metalmark butterfly (Apodemia mormo langei) is an endangered butterfly associated with the Antioch Dunes ecosystem in Northern California. Currently, the Lange’s metalmark butterfly is only found at Antioch Dunes National Wildlife Refuge, where the last remnants of the Antioch Dunes are preserved. The Lange’s metalmark butterfly is a subspecies of the Mormon metalmark butterfly (Apodemia mormo), which is a member of the Riodinidae family. This is the family that includes the metalmark butterflies. Lange’s metalmark butterflies have brown and orange coloring on the wings with white spotting. The Lange’s metalmark butterfly is the only metalmark butterfly that occurs at Antioch Dunes, and subtle differences in wing coloration differentiate it from other Mormon metalmark butterfly subspecies. Adult butterflies typically begin emerging (eclosing) in early August, and the flight season continues until mid- or late September. The Lange’s metalmark is univoltine, producing only one brood per year. Females lay eggs singly and in small clusters on host plants throughout the flight period. All life stages of Lange’s metalmark butterfly are closely associated with naked-stemmed buckwheat (Eriogonum nudum var. psychicola), which is the primary nectar source for adults, is used to lay eggs and as a larval food plant. The leaves of the larval host plant provide both food and shelter throughout the larval instar phases.

Lange’s metalmark butterfly is a subspecies of the Mormon metalmark butterfly (Apodemia mormo). All Mormon metalmark butterflies have brown and orange coloring on the wings with white spotting. Lange’s metalmark butterflies is identified by its location as the only Mormon metalmark butterfly subspecies that occurs at Antioch Dunes, along with subtle differences in wing coloration, which differentiate it from other Mormon metalmark butterfly subspecies.

All life stages of the Lange’s metalmark butterfly are closely associated with naked-stemmed buckwheat (Eriogonum nudum var. psychicola), which is the primary nectar source for adults, is used to lay eggs and as a larval food plant. The Lange's metalmark butterfly also uses other flowering plants as nectar and food resources, but naked-stemmed buckwheat is considered its primary food plant.  

Adult butterflies typically begin emerging in early August and may be observed until mid- or late September. Females lay eggs throughout the adult flight period. This butterfly produces only one brood per year. Females lay eggs singly and in small clusters on larval host plants in late summer. The leaves of the larval host plant provide both food and shelter throughout the larval instar phases. All life stages of Lange’s metalmark are closely tied to a variety of naked-stemmed buckwheat (Eriogonum nudum var. psychicola), which is the primary nectar source for adults, is used to lay eggs and as a larval food plant.