In their papers on various species of British Macro-Lepidoptera, Messrs. Hellins and Buckler furnish us with much better accounts of the external appearance of caterpillars than can be gained from the meagre and superficial descriptions which used to be thought sufficient; and, as they have not confined their descriptions to the full grown animals, but have followed the creatures through all their moults, they have, in several cases, incidentally shown how great a difference there is between the larva just hatched and the full grown caterpillar; especially in the case of some of the Rhopalocera thus treated by them. Mr. Riley, of America, has, in one or instances, recorded similar facts.