|Angled pierrot mudpuddling, Yeoor, Mumbai,India|
- For a key to the terms used see Lepidopteran glossary
Male upperside is dark brownish black, a broad medial oblique white band across both fore and hind wings, not extended on the fore wing above vein 5, above vein 3 produced shortly outwards and downwards into a hook-like form. Underside: white with the following black markings:—On fore wing a short, outwardly-pointed, oblique, clavate streak from base joined below to a semi-circular broad band that reaches the costa; a short, outwardly oblique, upper diseal bar, its outer edge generally emurginate; the apex, the terraen narrowly, a large irregular sub-quadrate spot touching it in the middle and a very large inwardly oblique irregular spot or mark close to the tornus. On the hind wing: a hook-shaped mark at base sometimes slender; an inwardly oblique short clavate bar from apex, three coalescent spots extended outwards from the dorsum above the tornus formed into a sinuate irregular mark; a spot further outwards in interspace 4; a terminal series of slender lunules and an anticilary fine line. Antennae, head, thorax and abdomen black; beneath: the palpi, thorax and abdomen white.
Female. Similar to the male on both upper and under sides, but on the former the white medial band is narrower, on the latter the black markings are broader. Antennae, head, thorax and abdomen as in the male.
The butterfly is found in Sri Lanka, peninsular India, Madhya Pradesh, south Bihar, Odisha, and in the Himalayas from Sikkim to Assam and onto Myanmar. The butterfly is also found in southern Sulawesi, Basilan, and Mindanao.
The butterfly flies rapidly, close to the ground visiting low flying bushes. Found along nullahs and shady paths. Visits damp patches.
Found in jungle and lightly forested country with moderate to heavy precipitation.
"Feeds on the tender leaves of the chorna (Zizyphus rugosa) .... pale green, of the usual woodlouse form, with the head concealed under the second segment. The whole body is more or less pubescent and there is a fringe of longer hairs on each side." (Davidson and Aitken quoted in Bingham, 1907)
"Short and stout, constricted between the thorax and abdomen, clothed with short hair, closely attached by tail and band to any convenient surface; colour ochreous mottled with brown." (Davidson and Aitken quoted in Bingham, 1907). 
Dry season form is smaller with less prominent markings.
- Krushnamegh Kunte (2000) (reprint 2006) Butterflies of Peninsular India : University Press India Pvt. Ltd., India
- Marrku Savela's Website on Lepidoptera Page on Caleta genus.
- Bingham, C. T. 1907 Fauna of British India. Vol 2. (Description of Castalius decidia)
- Haribal, Meena (1994) Butterflies of Sikkim, pg 9.
- Wynter-Blyth, M.A. (1957) Butterflies of the Indian Region, pg 259-260.