INTKODUCTION. XXV 
The collections formed during; the season of 1888 being of such a satis- 
factory character, I proposed to ISIr. Pratt that lie should proceed still 
fiu'ther up the river, and finally arranged Avith him that he should spend 
two years in working up the insect fauna of Western China, penetrating as far 
as he possibly could in the direction of the Thibetan frontier. As it appeared 
to me to be beyond the capabilities of one entomologist to secure anything 
like a fairly representative collection of the insects occurring in this rich 
country, I engaged a well-known German collector, Mr. Franz Ki'icheldorff, 
to join Mr. Pratt in the expedition, giving him special instructions to devote 
his energies to the Lyctcnidte, Hesperiidrc, and obscure Heterocera. Mr. Pratt 
being unable to find a native boat that fulfilled his requirements, had one 
specially constructed and fitted at Ichang, of which a full description and a 
photograph will be found in his book, ' To the Snows of Tibet through 
China.' 
Kricheldorff had now arrived at Ichang, and the boat being ready, a start 
was made for the West on March 26th, 1889. Chung-king was reached on 
April 21st, and on May 6th they arrived at the confluence of the Min river, 
up which they proceeded to Chia-ting-fu, where the boat was left and 
some of the crew instructed to collect insects in the neighbourhood, whilst 
Pratt and Ivricheldorft" journeyed overland to Ta-chien-chih, a village at the 
foot of Wa-shan, at which place they arrived on May 26th. The weather 
was very changeable, with much rain towards the end of May. Finding 
that the district around Wa-shan was a good collecting locality, Pratt 
engaged thirty natives to form entomological collections, and left them to 
work the district whilst he went on to Ta-chien-lu, where he arrived on 
July 4th. On the 25th of July he visited Che-tou, a Thibetan hamlet 
situate to the west and distant about one day's journey ; subsequently he 
made an expedition to the north of Ta-chien-lu, returning to that city on the 
14th of August, leaving again next day on his way back to Ichang, at which 
town he arrived on September 19th, having made short halts at Wa-shan 
and Chia-ting-fu to pick up the natives' collections. 
In 1890 they set out on their second voyage up the river to Western 
China on February ISth, reaching Chung-king on March 12th, and Chia- 
