^^^ 



90 COLIAS. B^j J. Bbher. 



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

 liacis. and in the middle and two blackish dots at the discocellulars. The $ has lighter ground-colour. — pacis Stgr. 

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

 r^l^ plesseni. is broader and the hindwing is more deeply dusted with red-brown. — plesseni sufesp. nov., from Chanchamayo 

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

 eastern slopes of the Andes, where the species Avas fljang together with Colias euxanthe over lupine-fields. It 

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

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

 the hindwing. 



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 

 than 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 C'oHas-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 them 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 the 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 Avanting. 



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. hoothii to lat. 15'^), 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, liA'e mostly on clover and allied plants, the species indigenous to 

 the north mostly on Yaccinium. Pupa with pointed head and raised, A^ery 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. 



palaeno. C. palaeno L. (= philomene Hbn., lapponica Stgr., Averdandi H.-Schaff.) (27a). I have before me 



a (^ from Canada, from the collection of Herr Leopold Haetmann of Wiirzburg (to Avhon I am indebted for 

 the loan of his North American Pierids). It is aboA-e not distinguishable from German specimans {europome Es-p.), 

 but much more j-elloAv on the under surface; the colouring of the hindAving approximates to that of the $$ of 

 Ijclidncides. europome. — At Hudson's Bay and in Alaska occurs pelidneides Stgr., Avhich according to Staudinger differs 

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

 hoAvever, commonly A-aries in this, j'et 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 

 black beneath, beloAv Avhich the white, black-edged spiracles are placed, venter and ventral legs dull green, 

 thoracic legs yelloAvish, head green; on Yaccinium uhginosum. Pupa greenish yelloAV with strongly convex 

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

 marshy ground. 



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

 than palaeno, and has narrOAver and less dark distal margin, the under surface is likeAvise much paler, greenish 



