178 
MICROLEPIDOPTERA OP NEW GUINEA 
Much attention has recently been paid to the peculiar fauna encountered 
in that valley by the Expedition. In spite of its high elevation of about 
1600 meters, the Grand Valley houses a number of lowland species which 
one would not expect to find at that altitude. This concerns birds (Rand, 
1941), Odonata (Lieftinck, 1949), and Rhopalocera (Toxopeus, 1950). 
The Grand Valley forms no exception in this respect, as the same pheno- 
menon was observed with Odonata, Rhopalocera, and Microlepidoptera 
of the environs of the elevated Wissel Lakes in West New Guinea and it is 
possible that several other isolated and as far unexplored valleys in the 
Snow Mountains Range possess the same peculiar element in their fauna. 
The Grand Valley has been described by Brass (1941) as to its location, 
geographical aspect, and flora, while Rand (loc. cit.), and Lieftinck 
(loc. cit.) discussed the origin of its fauna. These authors explain the 
presence of lowland elements by accepting that through the disappearance 
of forests Baliem Valley forms what is called an “area of disturbed con- 
ditions” of great extension. Lowland forms may have arrived there inci- 
dentally, transported by wind currents or — as far as potential migrants 
are concerned — through their own powers; in this grass plane they found 
favourable conditions agreeing with those in their original habitats in 
lower countries and were able to settle down; some of them developed 
new subspecies and even new genera. 
Toxopeus (loc. cit.) launches a different explanation by giving credit 
to the geological history of these parts. According to him the Grand 
Valley and other high-elevated valleys of the Snow Mountain Range, as 
also the region of the Wissel Lakes and Arabu River, were originally low 
lands and have been elevated together with their lowland fauna at the 
time of the rise of the Snow Mountains. They form now “lost worlds”, 
surrounded by crests of high mountains which isolate them; lowland 
forms inhabiting them must be regarded as relicts of the ancient autoch- 
thonous lowland fauna. 
This problem, which is only briefly touched upon here, is fascinating, 
and we were desirous to ascertain whether the results of the study of the 
Microlepidoptera would shed any more light on the subject. 
Although the amount of specimens collected in the Baliem Gamp is 
reasonable, the number of species represented is low, viz., seventeen only. 
There are no endemic genera among this material. Six species are endemic 
to the Grand Valley, viz.: 
Chionolhremma gracilis ; the genus is endemic and has twenty more 
species from other collecting camps in the Central Region. 
Meridarchis anisopa, an almost cosmopolitan genus with eleven more 
species from other camps. 
Cryptophasa iorhypara, belongs to a rich Papuan and Australian genus; 
the present species is closely allied to G. curialis, which was collected in 
seven other camps. 
Thiotricha chionochrysa, a species of a cosmopolitan genus, with extremely 
