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THE DISTRIBUTION OF BUTTERFLIES IN INDIA. 



By L. C. H. Young, b.a., f.e.s. 



{Read before the Bombay Natural History Society on 

 25th February 1904.) 



I would have liked to have written a paper on the distribution of 

 insects generally in our area, but unfortunately our knowledge of most 

 orders is at present too fragmentary for me to attempt it. I have, there- 

 fore, confined myself to a single group of the Lepidoptera — the butter- 

 flies — about which we can now speak with considerable certainty. At 

 the same time, the broad conclusions at which we may arrive will pro- 

 bably be at least equally true of all other orders. 



Mr. Comber in a recent paper described the limits of the Oriental 

 region to which the greater part of India belongs. It remains to speak 

 in detail of some of its sub-divisions. India falls into 4 regions — (1) 

 the Himalayas west of Sikkim, with Cashmere; (2) the Indo-Gangetic 

 plain ; (3) The peninsular area, i.e., the whole of India south of Nc. 2 

 and including Ceylon; (4) Assam — using the term In the wide sense of the 

 proposed new province (and including the Bhotan Terai) which shades 

 indefinitely into the Chinese and Burmo-Siamese regions. 



The insect fauna of No. 1 is in the main palearctic though containing 

 a large number of immigrant oriental species on the lower slopes, the 

 proportion increasing eastwards so that, coupled with our present ignor- 

 ance of the insects of Nepaul, it is impossible to draw a satisfactory bound- 

 ary between this region and No. 4. 



No. 2. The Indo-Gangetic plain has no proper insect fauna of its 

 own. The scanty lists of species to be obtained there contain nothing 

 but common immigrant species from the surrounding regions. 



In our present ignorance of Southern China it is not possible to 

 characterize adequately the fauna of No. 4. 



In this paper I want to deal only with No. 3, the peninsular or 

 Indian area proper. This country falls into 4, or perhaps 5, 

 natural regions. There is the central more or less treeless plateau 

 of Malwa, and what is loosely termed the Deccan, which corre- 

 sponds in poverty of species to the Indo-Gangetic plain. To the north 

 and east of these there is a wide area including the greater part of the 

 Central Provinces, Bundelkund, Chota Nagpur, Orissa and the Northern 

 Oircars, which for want of a better name T am calling Gondwana. To 



