fond of them, and I have already mentioned a wasp that caught them to store its nest with. Amongst the beetles there is a family that is just as much mimicked as the Heliconii are amongst the butterflies. These are the Lampyridae, to which the fireflies belong. Many of the genera are not phosphorescent, but all appear to be distasteful to insectivorous mammals and birds. I found they were invariably rejected by the monkey, and my fowls would not touch them. The genus Calopteron belonging to this family is not phosphorescent. In some of the species, as in C. basalis (Klug), the wing-covers are widened out behind in a peculiar manner. This and other species of Calopteron are not only imitated in their colour and markings by other families of beetles, but also in this peculiar widening of the elytra. Besides this, the Calopteron when walking on a leaf raises and depresses its wing cases, and I observed exactly the same movement in a longicorn beetle (Evander nobilis, Bates), which is evidently a mimetic form of this genus. In addition to being mimicked by other families of beetles, Calopteron is closely resembled by a species of moth (Pionia lycoides, Walker). This moth varies itself in colour; in one of the varieties it has a central black band across the wings, when it resembles Calopteron vicinum (Deyrolle), in another this black band is wanting, when it resembles C. basalis. Professor Westwood has also pointed out to me that the resemblance to the beetle is still further increased in the moth by raised lines of scales running lengthwise down the thorax. The phosphorescent species of Lampyridae, the fireflies, so numerous in tropical America, are equally distasteful, and are also much mimicked by other insects. I found different species of cockroaches so much like them in shape and colour that they could not be distinguished without examination. These cockroaches, instead of hiding in crevices and under logs like their brethren, rest during the day exposed on the surface of leaves, in the same manner as the fireflies they mimic. Protective resemblances amongst insects are so numerous and widespread, and they have been so ably described by Bates and Wallace, that I shall only mention a few of the most noticeable examples that came under my attention, and which have not been described by other authors. Amongst these were the striking modifications of some beetles belonging to the Mordellidae. These, in their normal form, are curious wedge-shaped beetles, which are common on flowers, and leap like fleas. In some of the Nicaraguan species the body is lengthened, and the thorax and elytra coloured, so as to resemble wasps and flies. In the Mordellidae the head is small, and nearly concealed beneath the large thorax; and in the mimetic forms the latter is coloured so as to resemble the large head and eyes of the wasp or fly imitated. The species that resembles a wasp moves its antennae restlessly, like the latter insect.