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 assigned to the tribe Pyrgini.
There are 11 Pachyneuria species, distributed variously from Mexico to Brazil and Peru. The adults are all very similar in appearance, with the exception of obscura, which has very dark veins but is otherwise almost devoid of markings.
Pachyneuria duidae is distributed from Venezuela to Peru.
Habitats
This species is found in tropical and subtropical evergreen rainforest at altitudes between about 400-1000m.
Lifecycle
I have no information regarding Pachyneuria, but Pyrgine butterflies typically lay their eggs singly on either the upperside or underside of leaves. The larvae are usually dull green or brownish, with thin longitudinal dorsal and lateral lines, and dark shiny heads, although some species are quite strikingly marked. Most Pyrgine larvae feed on herbaceous plants, but a small percentage feed on the leaves of bushes or trees. The pupae are generally dark and smooth, with the wing cases in a contrasting tone or colour. They are usually formed within silken tents formed by spinning together the leaves of the foodplant.
Adult behaviour
Pachyneuria are generally encountered as solitary males, seen imbibing mineralised moisture from river beaches.