Psychonotis caelius (C. & R. Felder, 1860) Psychonotis caelius is the most common and widely distributed type species of the genus. It displays some regional variability and currently eleven subspecies are known, covering almost the complete geographical range of the genus (Tennent, 1999: 115). Occurrence of nominate P. caelius is restricted to the Aru Islands and this taxon is characterized by its strongly reduced hindwing marginal lunules. Basal metallic on the hindwing is only weakly developed and costal metallic scaling on the forewing is reduced but the original illustration in Felder, Felder & Rogenhofer (1864: pl. 33, fig. 11-12) shows the typical green costal markings quite well. Characters of the type species were used to define the caelius species group of Müller (2003: 164) and members belonging to this group are characterized by the presence of green scales on the forewing underside costa and base. Hindwing marginal lunules are complete and metallic blue-green. However, these characters stand only in the areas discussed by Müller. Concerning Western New Guinea populations of caelius, the two names plotinus (Grose- Smith & Kirby, 1896) and, much less frequently, plateni (Grose-Smith & Kirby, 1896) were used in the past.

{"references": ["Tennent, W. J., 1999. The genus Psychonotis Toxopeus in the Solomon Islands, with descriptions of five new taxa (Lepidoptera: Lycaenidae). Australian Entomologist 26 (4): 115 - 123.", "Muller, C. J., 2003. Three new species of Psychonotis Toxopeus (Lepidoptera: Lycaenidae) from Papua New Guinea. Australian Entomologist 30 (4): 159 - 165.", "Grose-Smith, H. & Kirby, W. F., 1896. Rhopalocera Exotica, being Illustrations of New, Rare, and Unfigured Species of Butterflies. Rhopalocera Exotica [3] 2: 39 - 46, pl. 3 - 4 (Thysonotis) London, Gurney & Jackson."]}

Published as part of Schröder, Stefan, 2019, Notes on the genus Psychonotis (Lepidoptera: Lycaenidae) from Western New Guinea (Papua and Papua Barat), with description of a new subspecies of P. melane (Joicey & Talbot, 1916), pp. 79-86 in Sugapa Digital 11 (2) on page 80, DOI: 10.19269/sugapa2019.11(2).04, http://zenodo.org/record/3832901