species look alike, be divided among the whole 'mimicry ring,' as we may say. The advantage of the resemblance is thus obvious, and we can understand why a process of selection should develop among such inedible species which should result in their being readily mistaken for one another; we can understand why, in the neighbourhood of Fritz Müller's home, Blumenau, in the province of Santa Catarina in South Brazil, the Danaidæ, species of _Lycorea_; the Heliconiidæ, _Heliconius eucrate_ and _Eueides isabella_; and the Neotropinæ, _Mechanitis lysimnia_ and species of _Melinæa_, should all exhibit the same colours, brown, black and yellow, in a similar pattern, on similarly shaped wings. The agreement is by no means perfect in detail, but it can be noticed in all parts of South America inhabited by species of these genera, and the same differences which distinguish, for instance, the two species of _Heliconius_ flying in two different regions, also distinguish the two species of _Eueides_ and the two species of _Mechanitis_. In Honduras we find the same mutually protective company of inedible genera as in Santa Catarina, but represented by other species, which all differ from the species in Santa Catarina in the same characters, as, for instance, that they have two instead of one pale yellow cross-stripe on the anterior wings. The species are: _Lycorea atergatis_, _Heliconius telchinia_, _Eueides dynastes_, _Mechanitis doryssus_, and _Melinæa imitata_[5]. In the environs of Bahia this mimicry ring consists of the following species: _Heliconius eucrate_, _Lycorea halia_, _Mechanitis lysimnia_, and _Melinæa ethra_, as figured on Pl. II, Fig. 12, iv, and such a mutual assurance society has always one or other edible species as mimic. The larger the mimetic assurance company is, the less harm can mimics do to it. In the case figured it is two Pieridæ already known to us that have fairly well assumed the Heliconiid guise, namely, _Dismorphia astynome_ (Pl. II, Figs. 18 and 19) and _Perhybris pyrrha_ (Pl. II, Figs. 16 and 17). In the latter of these the male still has, on the upper surface, just the appearance of one of our common Garden-whites, while the female is coloured quite like the Heliconiidæ, but without having lost the form of wing of the Whites. The larger the mimetic company is the greater will be the protection afforded to its palatable mimics, since they will be the more rarely seized by way of experiment. It is, of course, obvious that in this kind of mimicry--that is, in the imitation of an unpalatable and rejected species for protection--it is presupposed as a general postulate that the edible mimics are considerably in the minority, as Darwin showed; for if it were otherwise their enemies would soon discover that among the apparently unpalatable species there were some which were pleasant to taste. Here, too, the facts bear out the theory, although exceptions can easily be imagined, and do seem to occur.