|Moorland clouded yellow|
Several, see text
Colias palaeno, known by the common names moorland clouded yellow, palaeno sulphur, and pale Arctic clouded yellow, is a Holarctic butterfly in the family Pieridae. As most Colias-species, it is an avid flyer. Though the species is normally restricted to the habitats, occasionally it is found far from suitable breeding grounds. The larva is found on bog bilberry (Vaccinium uliginosum).
Upperside of male pale yellow with blackish brown distal margins, pale-centred dark middle spot to the forewing and light middle pot to the hindwing; fringes red. Underside of forewing pale yellow with white-centred dark middle spot,the costal and distal edges being red; hindwing yellow, strongly dusted with fuscous, the large middle spot being mother-of-pearl colour, and the fringes red. The female has a white ground colour above, the underside of the forewing being white proximally, yellow at apex, the hindwing being somewhat paler in the female than in the male.
The larva is sea-green, velvety, bearing minute black dots; a lateral stripe bright yellow edged with black beneath, below the same the white black-edged spiracles; underside and abdominal legs dull green, thoracical legs yellowish, head green. The Pupa is greenish yellow, the back being strongly convex.
- Colias palaeno palaeno – Sweden, Norway, Finland, and Estonia
- Colias palaeno aias Fruhstorfer, 1903 – Japan the largest form of palaeno, the marginal band of the forewing being very broad and the underside rich green
- Colias palaeno baffinensis Ebner & Ferris,  – northern North America
- Colias palaeno chippewa W.H. Edwards, 1870 – northern North America, may be a separate species (C. chippewa)
- Colias palaeno europome (Esper, 1778) – Belgium, Germany, Slovakia, Romania, and Ukraine
- Colias palaeno europomene Ochsenheimer, 1808 – high altitude in the Alps. This form is somewhat larger than the nominate, the male lemon-yellow above, being below deeper yellow, as is also the female.
- Colias palaeno orientalis Staudinger, 1892 – Kamchatka very similar to europomene, being dark greenish on the underside of the hindwing
- Colias palaeno poktusani O. Bang-Haas, 1934 – North Korea
- Colias palaeno sachalinensis Matsumura, 1919 – Sakhalin
- Colias palaeno synonyma Bryk, 1923 – Sweden, Denmark
Colias aias is treated as a full species by some authors.
- Colias palaeno baffinensis, Butterflies of America
- Colias palaeno chippewa, Butterflies of America
- Colias chippewa at Markku Savela's Lepidoptera and Some Other Life Forms
- lignées boréo-alpines
- Colias at Markku Savela's Lepidoptera and Some Other Life Forms
- Josef Grieshuber; Bob Worthy; Gerardo Lamas (2012), Münchner Entomologische Gesellschaft, ed. (in German), The Genus Colias Fabricius, 1807: Jan Haugum'S Annotated Catalogue Of The Old World Colias (Lepidoptera, Pieridae), Pardubice: Tshikolovets Publications, ISBN 978-80-904900-2-4