21. On the Ground-plan of Wing-pattern in Nymphalids and certain other Families of the Rhopaloeerous Lepidoptera.
- 1A 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.
- 2The 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.
- 3The prototype is realized only partially in existing patterns; the formulæ of the latter are incomplete.
- 4In 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.
- 5The 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.
- 6A partial realization of the same prototype takes place in other families of Lepidoptera.