INTKODUCTION. 
xxix 
Pu-TSU-FONG. — There is only one hut at this place, which is situate on the 
Mo-si-mien Pass, two days' S.W. from Ta-chien-lu. It stands at an elevation 
of 7500 feet. The higher slopes of the mountains are covered with grass and 
lilies ; the valley below is all forest. Another station in this district was the 
" Log-cabin " in the forest, towards the summit of the Mo-si-mien Pass, at 
an elevation of 12,000 feet. This forest consists of rhododendrons and 
pines, and is three days' from Ta-chien-lu. 
IIow-KOW. — A small group of hamlets, ten days' W. of Ta-chien-lu. It is 
placed in a valley, and, according to Bishop Biet, a river here is considered by 
the Chinese to be the eastern boundary of Thibet. In this locality a fine 
collection was made by natives. 
A good deal of uncertainty exists concerning the exact boundary-lines 
of "Western China and Thibet ; but it is quite certain that all the localities 
visited by Pratt, Kricheldorff, and their collectors are situated in China 
proper. How-kow, which I previously considered to be in Thibet, is now 
said to be on the border-line. Mons. Oberthiir has erroneously referred 
Ta-chien-lu and its neighbourhood, and also Mou-pin, to Thibet instead of 
China. 
Besides the material accumulated by Pratt and KricheldorfF and the 
natives employed by them, valuable collections were sent to this country 
from time to time by the late Capt. Yankowsky, commander of one of the 
steamers plying on the Yang-tze-kiang, who had been taught by Pratt 
how to collect and preserve Lepidoptera. Before leaving Ta-chicn-lu, Pratt, 
on my behalf, engaged natives to collect insects during 1891, and I received 
the results of their season's work at the end of that year. This collection 
proved of considerable interest, having been mainly obtained on the high 
plateaux near the Thibetan frontier. In the following year Mr. H. Grose 
Smith acquired, through Mr. Pratt, another consignment of Lepidoptera from 
Western China, which comprised a number of species apparently captured at 
moderate elevations, among which were several new to science which have 
subsequently been described in ' Rhopalocera Exotica.' 
A short account of my own collecting experiences in China, Japan, and 
e 
