76 The Irish Nahcralist. [ March, 



feet above the sea-level in some instances, so that the islet in 

 question must have been continuously soaked by the deluge 

 of sea-water, and a hot dry season succeeding in 1894, ^^^ 

 thrift and grass became brown and dead, and the Silene showed 

 no signs of life. By careful searching onl}" a few C. bilineata 

 were to be found on the rocks, from some of which I secured 

 ova, the fate of which I have already narrated. At the end of 

 June, 1895, 1 could find no specimens ; and only in one sheltered 

 nook a little grass had sprung up. Some Silene, however, had 

 sprouted again from the roots and produced foliage and flowers, 

 and a little Sea Camomile and other small sea-plants had also 

 survived. It is therefore to be feared that this interesting 

 race has been extirpated, unless perhaps a few individuals 

 may have survived the famine by feeding on the plants above- 

 mentioned. There is also a chance that on other larger 

 islands the variety may exist. It now remains for me to 

 analyse the circumstances and environment which have given 

 rise to this extreme case of melanism. The cliffs and islands 

 which are found on this part of the coasts of Cork and Kerry 

 are of a dark slate formation, and in some cases of dark con- 

 glomerate. I have taken a considerable series of Cavipto- 

 gravivia bilineata from various points of this coast-line, and 

 find the ordinary bright yellow type frequent, but among them 

 unusual numbers of the banded form, and also numerous 

 specimens with the dark scaling of the waved lines much in- 

 creased, and an evident tendency toward darkened suffusion, 

 producing a great variety of dingy and dark striated aberra- 

 tions. 



The deepest mainland form, that of ab. infuscata, is rare, 

 and occurs with the rest, and not isolated, at Ballinskelligs 

 Bay and Dursey Island. This shows a further advance toward 

 melanism, and is in excess of any previously noted in the 

 British Islands, as stated {i7i lilt.) by Mr. Barrett, to v/hom I 

 sent the first specimen taken. In it the yellow forewings of 

 the type are darkened throughout by the mixture of dark 

 scales, giving them a dark yellowish brown hue, with the 

 central band and outer margin more darkly shaded ; the hind 

 wings being either a dingy brown or dull yellow. In all the 

 transitional aberrations taken (i.e., between the type and the 

 V. isolata), the hind wings were variable and apparently 

 responded partially only in a small number of instances to the 



