What importance we attach to this condition must depend upon our interpretation of the word "allies"--whether, for example, we use it for a small group of closely connected species, for a genus, for a group of genera, or in an even wider sense. Perhaps an example will serve to make the difficulty more clear. As already noticed, the S. American genus _Dismorphia_ belongs to the family of Pieridae or "whites." Also certain species of _Dismorphia_ bear a close resemblance to certain species of Ithomiines, a noteworthy example being _D. praxinoe_ and _Mechanitis saturata_ (Pl. X, figs. 3 and 7), in which the pattern, colour, and shape of the two species are all far removed from what is usually understood by a "white." It must not be forgotten, however, that these matters are generally discussed by European {58} naturalists who have grown up in a region where the majority of the "whites" are more or less white. For this reason the statement that _D. praxinoe_ differs from the bulk of its allies is likely to meet with general acceptance, especially as some of the species of the genus itself (e.g., _D. cretacea_, Pl. X, fig. 1) are regular whites in appearance. But when we come to look at the genus _Dismorphia_ as a whole the matter assumes another complexion. Seitz[29] recognises 75 species of which about a dozen are predominantly white. The rest present a wonderful diversity of colour and pattern. Black predominates on the fore wings, and the insect is frequently marked with gay patches of yellow, bright brown, scarlet, or blue. Forms which from their colour are clearly not mimics present nevertheless the general pattern and shape of other forms which bear a strong resemblance to some Ithomiine. Sometimes a change of colour in certain patches from blue or yellow to bright brown would make all the difference between a non-imitative and an imitative species. Moreover, the non-imitative forms frequently have the peculiar narrow wing, so unusual in a Pierine, which enhances the resemblance of the mimicking species to the Ithomiine model, and which to some extent occurs even in _D. cretacea_. Clearly we are not justified in saying that _D. praxinoe_ differs from the bulk of its allies, for inside the genus there are many non-imitative species which differ {59} from it in some particulars and are alike it in others. There is a distinct family resemblance among the bulk of the Dismorphias, including practically all the mimetic forms, and on the whole the resemblances between the imitative and the non-imitative forms are as noteworthy as the differences. Though not exhibited in so striking a fashion, the same is to a large extent true of a large proportion of the cases of mimicry. It is on the whole unusual to find cases where a single species departs widely from the pattern scheme of the other members of the genus and at the same time resembles an unrelated species. Two of the best instances are perhaps those of _Limenitis archippus_ (p.