90 COLIAS. By J. Bober. 



surface of the iiindwing is yellow, densely dusted with brownish and with red-brown spots at the costal marffin 

 ■parifi. and in the middle and two blackish dots at the discocellulars. The $ has lighter ground-colour. — pacis Siyr. 

 i. I. ('26(1), from Peru (3300 m), is above somewhat deeper yellow, beneath the reddish border of the forewing 

 plessoii. is broader and the hindwing is more deeply dusted with red-brown. — plesseni subsp. nor., from Chanchamayo 

 (Peru), was captured by Baron G. von Plessen on March 26 1906 on the way from Aroya to La Merced on the 

 eastern slopes of the Andes, where the species was flj'ing together with Colias euxantlie over lupine-fields. It 

 is above and beneath sulphur-yellow, has beneath no differently coloured border to the forewing and shows 

 only a little blackish dusting on the sulphur-yellow ground-colour apart from the blackish brown spots of 

 the liin<lwing. 



24. Genus: Colias F. 



About three-fourths as many species must be referred to the American Piegion as to the Palaearctic 

 if the conception of species is not applied too critically. But on a more thorough examination scarcely more 

 tlian twenty American species can be established, hence about half the number which the Palaearctic Region 

 produces. Considering the enormous size of the region this suggests an apparent poverty in species in America, 

 which however is explained when we remember that the species of Colias are in great part inhabitants of the 

 mountains, and the American Region properly shows only one mountain range, although an enormous one. The 

 splitting up of Central Asia into a number of independent mountain ranges has apparently been very favourable 

 to the formation of Co/f'rts-species. This advantage is wanting in the American Region. On the other hand 

 it must further be taken into consideration that the most southern part of America possesses a few species, some 

 of tliem very conspicuous, for which the eastern hemisphere can offer no equivalent owing to the want of cor- 

 responding lands. 



The genus Colias is unmistakeably characterised by its superficial appearance; whether the species comes 

 from the far north or the extreme south it is immediately recognised as a Colias. In neuration its special char- 

 acteristic is the entire absence of the precostal, in which the genus agrees only with tlie superficially very dif- 

 ferent Terias. The butterflies are mostly of medium size, some species are among the larger Lepidoptera. Antenna 

 rather short, with gradually thickened, but distinct club. Apex of the forewing rounded, forewing with four 

 subcostal veins, of which the first arises far before the discocellular; the upper radial arises from the subcostal, 

 hence the upper discocellular is wanting. 



The genus has its principal area of distribution in Central Asia, where most of the species have their 

 habitat. It is almost exclusively confined to districts with a temperate climate. In North America, in the moun- 

 tains of tropical South America and in the plains of the southern part of South America, as already said, a large 

 number occur, in Africa only two species (local forms of Palaearctic species), but in the Indo-Australian Region, 

 except in the Himalayas and the Nilghiri Hills, no species occurs. A few species extend far towards the north 

 (e. g., C. boothii to lat. 75°), and in Tierra del Fuego occurs one of the largest and most beautiful species {imper- 

 ialis). A few species occur in two generations, but most in only one. Sexual dimorphism is well developed 

 in most of the species, also dimorphism in the $$, which often occur in a pale and in a bright yellow or 

 orange-coloured form. Their flight is very quick and long-sustained. The (^(^ of many species possess as secon- 

 dary sexual character at the costal margin of the hindwing above a more or less sharply defined small disc of 

 thick chalky scales (,,Mehlfleck"). — Egg cylindrical, feebly ribbed. Larvae long, of almost equal width through- 

 out, with very short hairs; they hibernate, live mostly on clover and allied plants, the species indigenous to 

 the north mostly on Vaccinium. Pupa with pointed head and raised, very sharp dorsal side of the thorax; like 

 most Pierid pupae they are placed upright, are hooked at the cremaster into a silken pad and are held upright 

 by a long, loose girdle. 



jKiluciio. C. palaeno L. (= philomene Hbn., lapponica Stgr., werdandi H.-Schdff.) ('27a). I have before me 



a (J from Canada, from the collection of Herr Leopolu Hartmann of Wiirzburg (to whon I am indebted for 

 the loan of his North American Pierids). It is above not distinguishable from German specimans {europome Esp.), 

 but much more yellow on the under surface; the colouring of the hindwing approximates to that of the $$ of 

 pclidncidi's. europome. — At Hudson's Bay and in Alaska occurs pelidneides .S'/r/r., which according to Staudinger differs 

 from palaeno in that the median spot of the hindwing beneath is not white, but reddish as in pelidne; pelidne. 

 however, commonly varies in this, yet this median spot is always much smaller in that species than in palaeno. — 

 Larva sea-green, velvety, with fine black dots, at the sides a bright yellow longitudinal stripe margined with 

 Ijlack beneath, below which the white, black-edged spiracles are placed, venter and ventral legs dull green, 

 thoracic legs yellowish, head green; on Vaccinium uliginosum. Pupa greenish yellow with strongly convex 

 dorsum. In the Palaearctic Region the butterfly flies from the end of June to the middle of August on 

 marshy ground. 



pdidiic. C. pelidne Bdv. {= anthyale Stgr.) (27a), from Labrador and boreal North America, is paler yellow 



than palaeno, and has narrower and less dark distal margin, the undei- surface is likewise much paler, greenish 



