Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Weaver's Fritillary or Violet Fritillary (Boloria dia) is a butterfly of the Nymphalidae family. It is found in Europe, over the Caucasus up to Mongolia.The length of the forewings is 16-17 mm. The larvae probably feed on Viola species. A butterfly is a mainly day-flying insect of the order Lepidoptera, 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.