The experiments hitherto made by other observers, are not sufficient for deciding the question under consideration. Weir,[148] as is well known, showed that certain brightly coloured and conspicuous larvæ were refused by insectivorous birds; and Butler[149] proved the same for lizards and frogs. These experiments are unfortunately so briefly described, that in no case is the species experimented with mentioned by name, so that we do not know whether there were any Sphinx caterpillars among them.[150] I have likewise experimented in this direction with lizards, in order to convince myself of the truth of the statement that (1) there are caterpillars which are not eaten on account of their taste, and (2) that such larvæ possess bright colours. I obtained positive, and on the whole, very decided results. Thus, the common orange and blue striped caterpillars of _Bombyx Neustria_ enjoyed complete immunity from the attacks of lizards, whilst those of the nearly allied _Eriogaster Lanestris_ and _L. Pini_ were devoured, although not exactly relished. That the hairiness is not the cause of their being unpalatable, is shown by the fact that _L. Pini_ is much more hairy than _B. Neustria_. The very conspicuous yellow and black ringed caterpillar of _Euchelia Jacobææ_ gave also most decided results. I frequently placed this insect in a cage with _Lacerta Viridis_, but they would never even notice them, and I often saw the caterpillars crawl over the body, or even the head of the lizards, without being snapped at. On every occasion the larvæ remained for several days with the lizards without one being ever missed. The reptiles behaved in a precisely similar manner with respect to the moth of _E. Jacobææ_, not one of which was ever touched by them. The yellow and black longitudinally striped caterpillars of _Pygæra Bucephala_ were also avoided, and so were the brightly coloured larvæ of the large cabbage white (_Pieris Brassicæ_), which when crushed give a disagreeable odour. This last property clearly shows why lizards reject this species as distasteful. Both caterpillar and butterfly possess a blood of a strong yellow colour and oily consistency, in which, however, I could not detect such a decided smell as is emitted by that of the _Heliconinæ_ and _Danainæ_.[151]