days before hatching this colouration is lost and the brown head of the larvae becomes visible. The hatching process takes around 12 days, or longer if the eggs are at higher altitudes. To sustain itself the newly-hatched larva consumes its egg casings, which have sufficient nutrients for early larval stages. Larvae Percnodaimon larvae vary from dull grey to brown and have black anterior setae. The larvae have five instars, each of which take about a month in pleasant summer temperatures, but up to eight months over winter. For this reason the butterfly can stay in its larval stage for up to two years, and can be found almost year-round in an instar stage. The alpine grasses Poa colensoi, P. buchananii, and other Poa species are the larval food plant. These tussocks are common throughout the Southern Alps, but larvae are present only where the grass grows adjacent to rocky areas. Black mountain ringlet larvae are night feeders to avoid predators, which can easily spot them feeding on the tips of tussock blades. They spend little time feeding, but instead conceal themselves in nearby hiding spots. Pupa At the start of pupation the black mountain ringlet turns grey with brown speckles to match the surrounding stones. Unlike most butterflies pupae are suspended horizontally rather than vertically, and are attached to the undersurface of a rock with a large cremaster, a hook-shaped protuberance on the abdomen. Pupae have been found up to 3 feet away from the nearest food plant. The adult butterflies emerge 2 to 3 weeks later. Imago Adult black mountain ringlets are found in summer, from December to February, and the Patricks note that early versus late emergence is one of the characteristics distinguishing the undescribed species. This species is considered to live about a year in its adult stage, but as the larvae can take two or three summers to grow to full size there is a possibility that it can live up to four. This slow growth may reflect the extreme climate and conditions of New Zealand's Southern Alps. See also Butterflies of New Zealand References External links Black mountain ringlet discussed on RNZ Critter of the Week, 2 December 2022 Satyrini Butterflies of New Zealand Monotypic butterfly genera Taxa named by Arthur Gardiner Butler