Taking the evidence as a whole, we may say that it fairly suggests the existence of some connection between modern urban developments and the appearance and rise of the melanic varieties. More than that we cannot yet affirm. It is a subject in which problems open up on every side, and all of them are profitable subjects for investigation. Unhappily such animals are difficult to rear successfully in captivity for many generations, owing to their extreme liability to disease. Not the least interesting feature of the melanics is the fact that the black varieties provide about the best and clearest example of a new dominant factor attaching itself to a wild species in recent times. None of the cases are satisfactorily recorded or analysed as yet, but the evidence is clear that _doubledayaria_ is a dominant to its type, and in several other dark varieties, though the pigment deposited is not black, the records show that the increased amount of the pigment almost certainly is due to a positive factor. Of this, _Hemerophila abruptaria_ is a good example.[24] There are some irregularities in the results, but taken together they leave little doubt that the dark brown variety is a dominant and the light, yellowish brown a recessive. A curious parallel to the rise of the melanic moths in England is provided by the case of the Honey-creepers or Sugar-birds, in certain West Indian islands.[25] These birds of the genus _Coereba_ (_Certhiola_) range from Southern Mexico to the Northern parts of South America and through the whole chain of the West Indian islands and Bahamas except Cuba. There are numerous local forms, and many of the islands have types peculiar to themselves, as is usual in such cases. Some of the types or species range through several islands, but according to Austin Clark[26] no island has more than one of them. Cory[27] reckoned twelve such species within the Antillean region. They are small birds about the size of a nuthatch with a general colouring of black, yellow, and white. From the island of St. Vincent the Smithsonian Institution received in the late seventies of last century several completely black specimens in addition to two of the usual type of colouring. The black were described by W. N. Lawrence as _atrata_, and those marked with the usual yellow and white were called _saccharina_. The collector (Mr. F. A. Ober) reported that the black form was common, and that the _saccharina_ form was rarer. Lawrence remarks, "Had there been only a single example (of the black form) I should have considered it as probably a case of abnormal colouring, but it seems to be a representative form of the genus in this island."[28] There is of course no doubt of the correctness of the view taken by Austin Clark that "_atrata_" is a black variety. The black bird is in every respect, other than colour, identical with _saccharina_, and it is even possible to detect a greenish colour in the areas which would normally be yellow,