“The following remarks apply only to these species, although we may suppose with great probability that the whole of the congeneric forms--excepting perhaps the widely ranging species of _Acræa_--would display similar characters to their Brazilian representatives. “The imagines of the five genera mentioned form two sharply defined families, the _Acræidæ_ and the butterflies of the Maracujá group.[223] The latter comprises the three genera _Heliconius_, _Eueides_, and _Colænis_, which differ only in very unimportant characters; _Eueides_ is distinguished from _Heliconius_ by its shorter antennæ, and _Colænis_ differs from _Eueides_ in having the discoidal cell of the hind-wings open. The genus _Dione_ is further removed by the different structure of the legs, and the silvery spots on the underside of the wings. Certain species resemble those of other genera in a most striking manner, and much more closely both in colour and marking, and even in the form of their wings, than they do their own congeners. This is the case with _Acræa Thalia_ and _Eueides Pavana_, with _Heliconius Eucrate_ and _Eueides Isabella_, and with _Eueides Aliphera_ and _Colænis Julia_, which are deceptively alike, and the last two are connected with _Dione Juno_, at least by the upper side of the wings. The difficulty of judging of the relationships of the single species is thus much aggravated; it cannot be said how much of this resemblance is to be attributed to blood-relationship, and how much to deceptive imitation. “As larvæ all the Brazilian species must be placed _in one genus_, as they agree exactly in the number and arrangement of their spines (4 spines, not in a transverse row, on segments 2 and 3; 6 spines, in a transverse row, on segments 4-11; 4 spines, not in a transverse row, on the last (12th) segment). They differ from one another much less in this respect than do the German species of _Vanessa_, such, for instance, as _V. Io_ or _Antiopa_ from _V. Polychloros_, _Urticæ_, and _Atalanta_.[224] The larvæ of _Acræa Thalia_ are certainly without the two spines on the head which the others possess, and, on the other hand, they have a well-developed pair of spines on the first segment, which, in most of the other species, are completely absent; but this does not justify their separation, since the head spines of _Heliconius_, _Eueides_, and _Colænis Dido_, which are of a considerable length, are shorter than those of the next segment in _Colænis Julia_, and _Dione Vanillæ_, and in _Dione Juno_ they dwindle down to two minute points, this last species also bearing a short pair on the first segment. The larva of _Dione Juno_ is thus as closely related to that of _Acræa Thalia_ as it is to that of its congener _Dione Vanillæ_.