IN THE BRITISH ISLANDS. 27 



localities, with splendidly developed pale costae and all the character- 

 istic longitudinal markings of tritici, and without, or almost without, 

 any transverse markings. This creates another difficulty, and only 

 the most practised eye can distinguish some of these and correctly 

 refer them to their right species. I will not go so far as to say that 

 in some instances they cannot be named, but, except by the small 

 proportion of our oldest entomologists who have given this matter 

 special attention, I doubt whether they would be distinguished. But 

 although there is so much to increase the difficulty of determination, 

 yet I do not for one moment believe that cursoria and tritici are 

 specifically identical in the same way as are tritici and aquilina. My 

 Kent specimens are purely and simply cursoria-like varieties of tritici, 

 and I do not believe that cursoria occurs on that part of the Kent 

 coast from which so many cabinets have been supplied. I look upon 

 these similar varieties, therefore, simply as a development of parallel 

 variation in the allied species, but this parallelism is so complete that it 

 is really marvellous to me how, in the one species, tritici, all the 

 characters of all the allied species are developed in special forms, and 

 how these lead up to their respective extreme forms of development, 

 which have at last become distinct, or, as we call them, species. 



It has been pointed out to me that cursoria is a differently shaped 

 insect to tritici. My answer is that in this group, shape is nothing. 

 I have some remarkable forms of tritici with the wings almost as broad 

 as they are long, others, with wings long and exceedingly slender. 

 Normal well-developed tritici differ but little in shape from well- 

 developed normal cursoria ; but one factor in favour of considering 

 cursoria distinct, is the fact that at Sligo the wings are always well- 

 developed and ample, while it is unusual to find a specimen of any of 

 the various varieties of tritici, which is not exceedingly small and 

 undersized. It may be that the cursoria are more suited to their 

 environment, but there is no difficulty to distinguish the cursoria forms 

 from tritici taken on the same ground, while there is great difficulty 

 to distinguish cursoria from Sligo and the Lancashire coast, from 

 certain forms of tritici captured at Deal. 



We have now to consider another species obelisca. Until I 

 obtained Continental specimens and studied Continental authors, I must 

 own I did not know what the species was. I had, as most lepidopter- 

 ists I suppose have, specimens which had been obtained by exchange, 

 and which my correspondents undoubtedly believed were the species 

 they represented them to be. As those lepidopterists who believe they 

 get the species must supply those that know they do not, there must 

 be, I am afraid, a strange lot of obelisca in some cabinets. By some 

 occult method of reasoning on the part of my corrrespondents, nearly 

 all the obelisca I got were black (although the type is reddish-brown), 

 and, with one exception (two specimens which came from Paisley), 

 were tritici pure and simple, in a few cases worn until their specific 

 rank was a little dubious, in others exceptionally dark, but undoubtedly 

 tritici. With regard to obelisca, I feel dubious whether we get any ex- 

 treme forms of the redder or paler type. The Isle of Wight specimens 

 have been taken rather freely of late years by Mr. A. J. Hodges. The only 

 other localities in which they appear regularly to occur, are in Scotland. 

 Generally these latter are dark, darker than those from the Isle of Wight, 

 which still come undoubtedly near to var. hastifera, Donz. It does not 



