^* There are many cases among the Heterocera, where the larvæ alone are relied on for distinguishing speices, vide Weismann's Theory, p. 543, Eng. Ed. “In the sphingidæ, cases are not wanting in which the moths are far more closely allied than the larvæ. This is especially striking in the genus Deilephila, eight species of which are allied in the imaginal state, in a remarkable degree, whilst the larvæ differ greatly from one another in color, and to as great an extent in marking.” In the case of D. Euphorbiœ and Nicœa, whilst the larvæ show great differences * * * the moths cannot be distinguished with certainty. The imago of the rare Nicœa is, for this reason, wanting in most collections; it cannot be detected whether a specimen is genuine, i. e., whether it may not perhaps be a somewhat large example of Euphorbiœ.”