Introduction
The Pyrginae, popularly known as Flats or Spreadwings, are a cosmopolitan subfamily distributed across temperate and tropical habitats throughout the world. In the Americas there are 990 species, of which about 580 are placed in the tribe Pyrgini.
The genus Milanion contains 7 species, each with a similar pattern of hyaline spots on the forewing, and a broad white band traversing the hindwings and abdomen. Many of the species are difficult to tell apart, and can only be determined accurately by genitalic dissection.
Milanion cramba is endemic to Peru.
Habitats
This species occurs in forested habitats at elevations between about 200-800m. It is most commonly seen along narrow forest tracks, but sometimes ventures out into full sunlight to imbibe mineralised moisture from stones and boulders.
Lifecycle
The lifecycle appears to be unrecorded. Generally, Pyrgine butterflies lay their eggs singly on either the upperside or underside of leaves. The larvae are typically dull green or brownish, with thin longitudinal lines along the back and sides, and with black shiny heads. They feed typically on herbaceous plants, but a small percentage feed on the leaves of bushes or trees. The pupae are usually dark and smooth, with the wing cases in a contrasting tone or colour. They are normally formed within silken tents formed by spinning together the leaves of the foodplant.
Adult behaviour
Males are usually seen singly basking on low herbage, with wings outspread. They commonly feed at bird droppings.