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.
About 580 species are placed within the tribe Pyrgini.
The genus Sostrata is closely allied to Pythonides, Eracon and Quadrus. These genera comprise a total of about 45 small species, characterised by having a series of tiny transparent marks on their forewings, and a peppering of metallic blue scales overlaid on a dingy brown ground colour.
There are 8 species in the genus Sostrata, distributed variously from Mexico to Bolivia.
Sostrata festiva is known from Guyana, Venezuela, Brazil, Ecuador and Peru, but probably also occurs in Colombia, Bolivia and Argentina.
Habitats
This species occurs in rainforest and cloudforest habitats at altitudes between about 200-1400m.
Lifecycle
The lifecycle appears to be unrecorded. Generally, Pyrgine butterflies lay their eggs singly on either the upperside or underside of leaves. The caterpillars are typically dull green or brownish, with thin longitudinal lines along the back and sides, and with black shiny heads. They feed typically on low growing herbaceous plants, but some 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
The butterfly is usually encountered singly, and is active mainly in the early afternoon. Males are usually seen when basking on foliage. They do not normally indulge in mud-puddling, but they can be baited with shrimp paste applied to tree trunks or logs.