170 
MICROLEPIDOPTERA OP NEW GUINEA 
After the general remarks on the distribution of the apodemic genera 
we will more closely consider various relationships of the fauna of the 
Central Region, starting from the families, but before doing so we wish to 
give a short review of the endemic genera in order to stipulate the im- 
portance of this element in the New Guinea fauna, proving its independent 
character. 
Endemic fauna 
The endemic element of the entire fauna of the Central Region is con- 
siderable and amounts to 84 genera and their 202 species, together with 
the 366 endemic species of the apodemic genera totalling 668 endemic 
species and subspecies out of the 580 collected altogether, or not less than 
98 per cent. This high ratio of endemism is not surprising. In our opinion, 
only a small and not important part of it might be ascribed to errors due 
to our limited knowledge of the faunas of the neighbouring regions. 
Principally this endemism must be attributed to the independant character 
of the fauna of New Guinea. The complicated geological history of this 
immense island which, according to recent view's, arose out of the fusion 
of an old archipelago; its structure bears evidence of violent tectonic 
movements. Its rich flora, and tropical climate, together with factors 
unknown, are responsible for the fact that this island is inhabited by one 
of the richest insect faunas of the Tropics. 
It appears that in every isolated mountain range, or deep valley of 
Central New Guinea new T species and subspecies may be expected to 
occur, often at a few' miles’ distance as the crow flies from other collecting 
stations, but sufficiently separated and isolated by climatological and 
other barriers. Toxopeus has more than once pointed out that the true 
distance between the habitats of two different forms living on opposite 
slopes of a steep mountain range is not a straight line on the map between 
these localities but the isoclimatic line following the valley, down to its 
junction with the adjoining valley and going up that valley which often 
means distances of many miles. 
The present material offers all the more variety, since the collecting 
stations w r ere separated not only in horizontal but also in vertical sense 
and generally are situated at intervals of about 200 meters of altitude. This 
variation is clearly demonstrated by such plastic genera as the Tortricids 
Anisotenes, Parachorista, the Gelechiid Lecithocera, the Yponomeutid 
Lactura and many other, every collecting station of the Expedition often 
housing vicarious species distinct from those in the previous and the 
following stations along the Expedition’s route. 
Not only this longitudinal and altitudinal isolation of the collecting 
stations seems to be responsible for a great variation of the collected 
material: in a single camp a true explosion of local species may occur. 
The Moss Forest Camp is a striking example. In one month’s time in this 
station alone almost one-third of the entire collection has been made! 
