1912.] Introduction, 3 



27th by boat-convoy to Kobo, and leaving there a few days later 

 arrived in Calcutta on the evening of April 3rd. 



The Abor country lies in the N. E. corner of the Indian 

 Empire and is bounded on the east by Mishmi country, on the 

 north by Tibet, on the west by the land inhabited by the Miris 

 and on the south by the Brahmaputra River. Plate I, which 

 is reproduced b}^ permission from the maps made during the 

 expedition by officers of the Survey of India under Capt, O. H. B. 

 Trenchard, R.E., shows the routes which I traversed and the 

 principal places at which collections were made. 



In a north and south direction the Abor country extends for 

 about 80 miles. ^ Between the base camp at Kobo and Janak- 

 mukh and Balek it consists of an alluvial plain situated at a height 

 of 400 to 600 feet above sea-level and clad with dense jungle inter- 

 spersed with open patches of long grass or chapris. In some places 

 the jungle has at one time or another been cleared for cultivation, 

 but the older clearings are for the most part so thickly grown with 

 scrub and creepers as to be almost impenetrable. To the north of 

 this the country is a maze of hills, often precipitous, and inter- 

 sected by the boulder-strewn courses of the numberless small 

 streams that drain into the Dihang river. All the hills were 

 originally clothed from foot to summit with tree-jungle, but fre- 

 quently, more particularly in the vicinity of the Abor villages, 

 large tracts of country have been cleared. Man^^ such areas have, 

 after a period of years, been discarded for cultivation purposes and 

 soon develop thick scrub -jungle. 



The majority of the specimens obtained were found at com- 

 paratively low altitudes between 400 and 2,500 ft., but some were 

 taken at greater heights up to about 5,000 ft. and part of a small 

 collection of insects, made for me by Mr. J. Coggin Brown of the 

 Geological Survey, was obtained on Geku hill at a height of about 

 10,000 ft. Bapu, the highest of the foot-hills proper, reaches an 

 altitude of 6,390 ft. 



As regards invertebrates, the best results were obtained by 

 searching under bark and in rotten wood and large collections were 

 made by this means alone. In particular some dead and partially 

 decayed jack-fruit trees, which were being cut by the 32nd Sikh 

 Pioneers in the vicinity of Rotung, afforded admirable material ; 

 many of the branches were hollow and bored and when split open 

 were found to be literally filled with a varied assortment of Cara- 

 bidae, Staphylinidae, Passalidae, Endomychidae, Heteromera, 

 Rhynchophora, Dermaptera and Blattoidea along with representa- 

 tives of many other groups. Considerable collections were also 

 made under stones and numerous interesting species were found in 

 this situation. 



1 Only the southern portion of the Abor country is shown on the map (PL I): 

 the great ranges further to the north were not visited. 



