Castalius 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...

 genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 in the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Lycaenidae

Lycaenidae

The Lycaenidae are the second-largest family of butterflies, with about 6000 species worldwide, whose members are also called gossamer-winged butterflies...

. They are commonly known as pierrots. This name is also often used for the very closely related genus Tarucus

Tarucus

Tarucus is a butterfly genus in the family Lycaenidae. They are commonly known as blue pierrots or simply "pierrots". But the latter name is often used for the very closely related genus Castalius. In fact, the delimitation of Castalius versus Tarucus is not yet fully resolved, with some species,...

.

In fact, the delimitation of Castalius versus Tarucus is not yet fully resolved, with some species, such as the Dark Pierrot (T. ananda), having been moved between the two genera repeatedly. Regardless of how this may turn out, the Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

n species formerly placed in Castalius are now in Tuxentius

Tuxentius

Tuxentius is a butterfly genus in the family Lycaenidae. They are commonly known as pied pierrots or pies. Contained in this genus are the African species formerly placed in Castalius, except the Blue-eyed Pierrot which is separated in Zintha.-Species:The members of genus Tuxentius are:* Tuxentius...

(pied pierrots) and Zintha

Zintha

Zintha is a butterfly genus in the family Lycaenidae. It is monotypic, with the only species being Zintha hintza, the Blue-eyed Pierrot, Blue Pied Pierrot or Hintza Blue...

(Blue-eyed Pierrot), which are also very close relatives (in particular the former).

Species

Only four species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 are placed in Castalius nowadays. But as noted above, it may be that Tarucus and the present genus are eventually regarded as synonymous. In that case, the older name Castalius would again apply to the two dozen species in question.

• Castalius clathratus (Holland, [1891])
• Castalius fasciatus (Röber, 1887)
• Castalius fluvialis (Grose-Smith, 1895)
• Castalius rosimon
  Castalius rosimon
  The Common Pierrot is a small butterfly found in India that belongs to the Lycaenids or Blues family.-Distribution:Sri Lanka. India, Myanmar; Tenasserim, extending into the Malayan Subregion...
  
  – Common Pierrot