Home / Brush-Footed (Nymphalidae) / Milbert’s Tortoiseshell (Aglais milberti)

Milbert’s Tortoiseshell (Aglais milberti)

Milbert’s Tortoiseshell

The Milbert’s Tortoiseshell is the sole species of the Aglais genus present in North America. There has been a controversy regarding their actual genus as some consider it to be nymphalis, with both of them being unified at one point of time.  It is even said that butterflies of the aglais genus have a brighter hue.

Description and Identification


Milbert’s Tortoiseshell Caterpillar

The larva is black with spiny projections.

Scientific Classification

  • Family: Nymphalidae
  • Genus: Aglais
  • Common names: Fire-rim tortoiseshell
  • Scientific Name: Aglais milberti


Milbert’s Tortoiseshell Chrysalis

The pupa is brown with an outline of black.

Adult Butterfly

Sexual Dimorphism: Present

Color and Appearance: When opened, the upper sidewith orange bands that gets lighter and becomes yellow when it reaches the inner edge. The fore as well as hind wings have black borders while the latter may also possess small, blue spots. When closed, they are black with a brown band.

Aglais Milberti
Milbert’s Tortoiseshell Butterfly

Average wingspan: 4.2 cm to 6.3 cm

Flight pattern: Fast


Milbert’s Tortoiseshell Eggs

The eggs are round and green in color.

Quick Facts

Distribution Throughout the western and eastern United States, and also the whole of Alaska and Canada
Habitat Near wet wood lands, moist marshes and pastures
Lifespan adults Approximately 10 days
Host plants Lilac, thistles, goldenrod
Adult diet Nectar of flowers as well as dung, plant sap and rotting fruit

Did You Know

  • They have four subspecies namely Aglais milberti milberti, Aglais milberti viola, Aglais milberti furcillata, and Aglais milberti pullum.

Fire-rim Tortoiseshell
Milbert’s Tortoiseshell Images
Milbert’s Tortoiseshell Pictures

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