21. On the Ground‐plan of Wing‐pattern in Nymphalids and certain other Families of the Rhopaloeerous Lepidoptera.

Summary. A prototype (schema) of the wing‐pattern is constructed (Pl. I. fig. 1), which is intended as a ground‐plan of the pattern in the families Satyridæ, Morphidæ, Brassolidæ, and Nymphalidæ. The prototype is composed of a number of dark stripes and spots, which are designated by corresponding terms. The formula of the pattern may be obtained by writing together the indices of these terms. The prototype is realized only partially in existing patterns; the formulæ of the latter are incomplete. In each of the families mentioned a series of patterns may be found which complement each other, and in this way it may be shown that a family realizes the prototype with sufficient compléteness. In summing up the incomplete formulæ of existing patterns we obtain a more or less complete formula of the family. The general significance of the prototype is strengthened by the fact that about a half of the Rhopalocerous (s. str.) genera (excl. Hesperidæ) belong to the four families studied. A partial realization of the same prototype takes place in other families of Lepidoptera.