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ON NEW OR LITTLE-KNOWN DELIAS FROM 

 NEW GUINEA. 



By Dr. K. JORDAN. 



n~^HE new forms of the Pierine genns Delias here described were collected by 

 -L Mr. A. S. Meek in the mountain range which traverses the southern part 

 of Dutcli New Guinea, with the excejition of two forms which came from British 

 New Guinea. Our indefatigable traveller at first tried in vain to reach a suffi- 

 ciently high altitude in this difficult region, but by dint of perseverance 

 succeeded in attaining his object. On the first expedition into the interior he 

 followed the Oetakwa or Setekwa River, and did not get beyond the lower spurs 

 (3IJU0 — 4000 ft.) of the mighty Snow Mountains. The collection brought together 

 there, although containing a large number of very fine moths, was disappointing 

 as regards butterflies. Most of the species were widely distributed, and more or 

 less common. But there was among them a long series of Delias discus Hour. 

 (1886), a peculiar and handsome species of which less than half a dozen specimens 

 existed in collections. 



Early this year A. S. Meek again left the coast for the interior, selecting this 

 time, as a means of ingress, the Eilanden River, which reaches the sea about a 

 hundred miles to the east of the Oetakwa River. Following the Eilanden River, 

 he reached the mountains in a north-easterly direction, and struck camp on the 

 slopes of Mount Goliath, at an altitude of .5000 ft. approximately. The mountain 

 is situated about 139" east of Greenwich. Here Meek remained during January, 

 February, and March. Butterflies were scarce at that season, with the exception 

 of Delias, of whicli there is a wonderful variety, some species being represented 

 by long series of specimens. 



The mountain Delias are undoubtedly one of the most interesting features 

 of the butterfly fauna of the island. It has now been jjroved in three diflerent 

 ranges of mountains — the Arfak and the Snow Mountains of Dutch New Guinea, and 

 the Owen Stanley range of the British territory — that above a certain altitude, 

 varying from three to five thousand feet, there exists a far larger number of 

 J)elias than anywhere else, most of the species not being represented outside 

 New Guinea by allied forms. 



The superabundance of species of any genus or family in a certain district 

 is generally considered evidence tiiat this district is the original home of that 

 genus or family, and is likewise often bronght forward as showing that the 

 species originated in their home by a small number of ancestral species splitting 

 up into a larger number without any geographical barrier having isolated one 

 incipient species from the other. It appears, indeed, plausible at first sight that 

 the eighteen new Delias which E. Weiske — and some years later A. S. Meek — 

 discovered in the Owen Stanley range, as practically occurring side by side, 

 originated as such in these mountain fastnesses, and originally did not come from 

 anywhere else. However, tlie recent discoveries in the Arfak and Snow Mountains, 

 while confirming the creative power of the different ranges, bring the geographical 

 element in the origin of these species much into the foreground. 



