The Western Hillside Brown (Stygionympha vigilans) is a butterfly

Butterfly

A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...

 of the Nymphalidae

Nymphalidae

The Nymphalidae is a family of about 5,000 species of butterflies which are distributed throughout most of the world. These are usually medium sized to large butterflies. Most species have a reduced pair of forelegs and many hold their colourful wings flat when resting. They are also called...

 family. It is found in South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

 on the seaward side of the mountains from Cederberg

Cederberg

The Cederberg mountains and nature reserve are located near Clanwilliam, approximately 300 km north of Cape Town, South Africa at about . The mountain range is named after the endangered Clanwilliam Cedar , which is a tree endemic to the area. The mountains are noted for dramatic rock...

 south to the Cape Peninsula

Cape Peninsula

The Cape Peninsula is a generally rocky peninsula that juts out for 75 km into the Atlantic Ocean at the south-western extremity of the African continent. At the southern end of the peninsula are Cape Point and the Cape of Good Hope...

 in the western Cape

Western Cape

The Western Cape is a province in the south west of South Africa. The capital is Cape Town. Prior to 1994, the region that now forms the Western Cape was part of the much larger Cape Province...

 and along the Drakensberg mountains to Grahamstown

Grahamstown

Grahamstown is a city in the Eastern Cape Province of the Republic of South Africa and is the seat of the Makana municipality. The population of greater Grahamstown, as of 2003, was 124,758. The population of the surrounding areas, including the actual city was 41,799 of which 77.4% were black,...

 in the eastern Cape

Eastern Cape

The Eastern Cape is a province of South Africa. Its capital is Bhisho, but its two largest cities are Port Elizabeth and East London. It was formed in 1994 out of the "independent" Xhosa homelands of Transkei and Ciskei, together with the eastern portion of the Cape Province...

.

The wingspan

Wingspan

The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...

 is 45-48 mm. Adults are on wing from October to December and from August to April (with peaks from October to November and February). There are probably multiple generations per year.

The larvae feed on Poaceae

Poaceae

The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...

 grasses. Larvae have also been reared on Ehrharta erecta

Ehrharta erecta

Ehrharta erecta is a species of grass also known as panic veldtgrass. The species is native to Southern Africa and Yemen. It is a documented invasive species in the United States, New Zealand, Australia, southern Europe, and China....

and Ischyrolepsis cinncinnata.