TO the September number of Spolia Zeylanica Prof. Punnett contributes an important paper, illustrated by two double coloured plates, on mimicry in Ceylon butterflies, with a suggestion as to the nature of polymorphism. After giving a list of the hitherto recorded instances, which are relatively numerous in comparison with the extent of the fauna, the author points out that this mimicry is far less striking among the living insects than in museum specimens.- Not only is this difference apparent on the under surface of the wings when the insects are at rest, but it is still more noticeable in the mode of flight, so that with very little experience the eye learns to distinguish between the mimic and the mimicked. In the well-known case of Papilio polyotes, with its three phases of females, one of which closely resembles the male of the same species, while the second mimics the male of P. aristolochiae, and the third that of P. hector—both the two latter being inedible, while the first is edible—the author observes “that though model and mimic may be readily distinguished at rest, whether with wings expanded or closed, yet the resemblance between them may be sufficient to deceive such enemies as attack them when flying. Such, however, is certainly not the case. The mode of flight of P. polyotes is similar for all three forms, and is totally distinct from that of P. hector and P. aristolochiae.