436 



NA TURE 



{March lo, 1887 



experiment was not more decisive than the other. Not 

 only did luminous appearances accompany the setting-in 

 of a current towards the earth from the network of 

 insulated wires spread over the summit of Mount Ora- 

 tunturi, but the light evoked was distinctively auroral. 

 Examined with the spectroscope, it yielded the still 

 enigmatical " citron-line " discovered by Angstrom in 1 867. 

 This is the invariable and chief constituent of auroral 

 radiations. Besides one fitfully present, detected by 

 Zollner in the red, it is the only vivid line its spectrum 

 includes. Ten others, more or less dubiously enumerated, 

 are faint, hazy, indeterminate. M. Lemstrom holds that 

 there is a fair agreement between some of them and lines 

 in the laboratory-spectrum of rarefied air. But this is 

 perhaps a too sanguine opinion. These seeming coin- 

 cidences are very loose, and have not been drawn closer 

 by careful inquiry. Vogel's conclusion that the spectrum 

 of the aurora is modified from that of atmospheric air is 

 indeed highly probable, but its probability is derived far 

 more from external than from internal evidence. 



A. M. Cl.F.RKE 



THE BUTTERFLIES OF INDIA 



The Butterflies of India, Biirmah,andCeylon. A Descrip- 

 ' tive Hand-book of all the Known Speciesof Rhopalocer- 

 ous Lepidoptera inhabiting that Region, with Notices of 

 Allied Species occurring in the Neighbouring Countries 

 along the Border. With Numerous Illustrations. By 

 Lionel de Nicifville, F.E.S. Vol. II. Royal Svo. 

 (Calcutta. London : Bernard Ouaritch, 1886.) 



IVTORE than four years have elapsed since the first 

 part of this book was published, and one of the 

 authors has been obliged to resign his share in the work. 

 The second volume, which has been written by Mr. 

 de Niccville alone, is in no way inferior to the first. 

 When we remember that in the trying climate of Calcutta, 

 and only in the leisure hours which can be spared 

 from official work, Mr. de Nicdville has with but very 

 trifling assistance from the Government of India com- 

 pleted a volume of nearly 300 pages, containing over 

 300 species of butterflies, we must allow that he deserves 

 great praise ; and though a volume produced under 

 such difficulties must of necessity contain faults, yet 

 it is in every respect very superior to Mr. Moore's work on 

 the Lepidoptera of Ceylon, which was largely subsidised 

 by Government. There is no doubt that the impetus 

 given to the study of the butterflies of India by the pub- 

 lication of this work will have the best results, and we 

 have every reason to hope and believe that it may be 

 completed in three or four years more at latest. The 

 present volume is devoted almost entirely to the family of 

 Nymphalinie, and brings up the number of Indian butter- 

 flies already described to over 600, all of which are treated 

 in a thoroughly scientific, careful, and painstaking manner. 

 Though the author has gathered to his assistance a 

 growing band of field workers in various parts of India, 

 among whom Messrs. Miillcr, Knyvett, Graham A'oung, 

 Colonel Swinhoe, and others are conspicuous, and is 

 rapidly accumulating a large quantity of specimens from 

 all parts of the country, he still labours under the diffi- 



culty of being unable to see the types of many of the 

 so-called species described by Messrs. Butler and Moore 

 in Europe. Evidence is constantly being brought for- 

 ward to confirm the opinion of most entomologists, 

 that a large proportion of the names given by these 

 authors represent no fixed or constant varieties, and 

 that the characters described by them cannot be recog- 

 nised in the insects themselves ; but it is impossible to 

 ignore them until this can be proved by comparison of 

 these types with large series of specimens. Under these 

 circumstances, Mr. de Nicevillehas acted wisely in print- 

 ing the descriptions of all these doubtful species, so that 

 the attention of collectors may be called to them, and their 

 existence proved or disproved. His remarks on them 

 have the advantage of being intelligible, which is not 

 always the case with the original descriptions of the 

 authors in question, who have had for some years almost 

 a monopoly in the description of Indian butterflies. 



The kind of difficulty which occurs in many instances 

 may be illustrated by the author's final remarks on the 

 numerous varieties of the genus Abisara, described as 

 species by Mr. Moore. 



" A prunosa is typically the darkest coloured, and in 

 the male most brilliantly purple-shot, of this group of the 

 genus, specimens from Travancore being particularly 

 large and dark. Even among Ceylon specimens, how- 

 ever, I find considerable variation ; in some males the 

 inner discal band on the fore-wing is evenly convex, and 

 in others distinctly angled in the middle, and the purple 

 suffusion is also variable ; the size and number of the 

 black spots on both sides of the hind-wing is extremely 

 inconstant. In one very abnormal specimen there are 

 two sub-apical spots, only the anal ones bemg entirely 

 wanting. From an island one would expect to find some 

 distinguishing characters in a species supposed to be 

 peculiar to it, but I have quite failed to discover any. I 

 can only repeat that, in my opinion, the name echerius 

 should apply to all the species of this group of the genus 

 Abisara, except perhaps to the Andaman local race, which 

 has been named bifasciata ; that as, in this case, the 

 geographical range of numerous slight local races is not 

 segregated, and each local race must interbreed with the 

 next on the boundary-line which is supposed to separate 

 them, it can serve no good scientific purpose to pick 

 out a few apparently different specimens from each local 

 race and to describe them, at the same time ignoring the 

 intergrade specimens which exist." 



If this opinion had been more generally held, the study 

 of the butterflies of India would have been much simpli- 

 fied, and it is to be hoped that a new edition of '• The 

 Butterflies of India," which will certainly be called for 

 almost before the first is complete, will show a large 

 reduction in the number of names. A fixed nomenclature 

 is the first desideratum in this as in other branches of 

 science, and tends more than anything to attract good 

 workers, who are often disgusted by a long list of 

 synonyms and by changes in well-known old names. 



The keys to the genera and species have been worked 

 out very carefully, and will be useful to beginners. The 

 literature, geographical distribution, and variation of each 

 species are also well and carefully done. The volume 

 will be indispensable to lepidoptcrists generally, and 

 ought to interest many in India, who have hitherto looked 

 on the collection of butterflies as rather a pastime than a 

 science. H. J. Ei.wk.s 



