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XVIII. The Ehopalocera of the Mt. Everest 1921 Expedition. 

 By N. D. Riley. 



[Read Octobci' IStli, 1922.] 



Plates XXXVI, XXXVII. 



The following list is in some respects disappointing, a 

 number of species, such as Parnassius invperalor atigustus, 

 Polygonia inter posita agnicnla, etc., which one would 

 expect to find, not being represented in the collection at 

 ail. On the other hand, the seven (possibly eight) new 

 species and forms collected represent a very fair percentage 

 on a total of only thirty-three (or possibly thirty-four) 

 species obtained altogether by the Expedition. Nearly 

 all the new forms are from the comparatively lower regions 

 — such as Kharta, Nyenyam and the Rongshar Valley, 

 the upper ends of deep gorges which cut through the 

 Himalayas from Nepal. It would be difficult to explain 

 the presence, within a few miles of Mt. Everest, of such 

 species as Catopsilia crocale and Colias fieldi were it not 

 for the existence of these valleys. 



The highest altitude at which Rhopalocera were collected 

 was at 18,500 ft., at the camp on the moraine shelf above 

 the Rongbuk Glacier a short distance N.N.W. of Mt. 

 Everest. Here Parnassius acco and epaplms and Vanessa 

 caschmirensis and ladakensis were met with, but no other 

 species. Above it Rhopalocera do not seem to exist 

 anywhere in the Indo-Tibetan frontier region. 



The specimens collected by Mr. A. F. H. Wollaston are 

 indicated by {W.); these have become the property of the 

 British Museum (Nat. Hist.). Those collected by Mr. Bul- 

 lock and presented by him to the Hope Department, 

 Oxford University Museum, are indicated by {B.). The 

 third collection, made by Major Morshead, who was attached 

 to the Expedition, is in the possession of Colonel Evans, 

 who has very kindly sent me a hst of it, which is appended. 



My thanks are due to Prof. Poulton for allowing me to 

 work out Mr. Bullock's collection, and for duplicates, 

 and also to Mr. Wollaston for the following note on the 

 localities. Further details on this last point can be found 

 in the Journal of the Royal CJeographical Society. 



TRANS. ENT. SOC. LOND. 1922. — PARTS III, IV. (FEB. '23) 



