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Show 196 MR. E. B. POULTON ON THE PROTECTIVE [Mar. 1, by the Frogs, and probably in the case of the Spiders also (in fact, Mr. Butler states that this was the case), but a bite from a Lizard would always be very serious and generally fatal. Mr. Butler states that the Lizards seized the distasteful larvse before rejecting them, although this may not have been in many instances. Mr. Butler has kindly given me an account of some further experiments upon birds, the results of which are included in the Tables below. Professor Weismann (' Studies in the Theory of Descent,' Part IL, pp. 336-340, English translation by Prof. Meldola) also experimented with Lacerta viridis, with the results that the following brightly coloured distasteful larvse were refused :-Clisiocampa neustria, Euchelia jacobaa, Pggara bueephala, Pieris brassica, Deilephila galii. On the other hand, the very highly conspicuous larvse of Deilephila euphorbia were eaten, as also were those of E. lanestris and Lasiocampa pini. The young larvae of Lasiocampa rubi, at a stage when they much resembled those of the rejected E. jacobaa, were eaten after cautious examination. Professor Weismann also regarded the larva of Papilio machaon (always rejected) as conspicuous ; but from my own experience I should certainly consider it well concealed upon its food-plant, and I should exclude it from the category of conspicuous larvse which support Wallace's suggestion. M y own experiments were conducted with greet Tree-Frogs (Hyla arborea, var. meridional is), and with Lizards of the following species:- Laeeita viridis, L. murulis (chiefly var. tiliguerta), and Tarentola mauritanica. M y diary, printed in the form of Appendix II. to this paper, will give all the details, dates, &c. of the various experiments made during the summer of 1886, so that it is unnecessary to further allude to them here. Finally, when a few weeks ago I told Mr. Jenner Weir of my intention to bring togpther all the experimental evidence upon this subject, he most kindly sent me the notes of his own observations during 1886, for incorporation in this paper. His experiments were conducted with the following species of Lizards: - Lacerta viridis, L. agilis, and Zootoca vivipara, and the diary is also printed in full as Appendix I. It now remains to tabulate the results of all tbe experimental evidence upon conspicuous larvse detailed above or desciined in the Appendices. Before doing so, it is necessary to recall Wallace's original suggestion, " that brilliant or conspicuous larvse would be found to be refused by their enemies : " that is to say, they will be found to possess some unpleasant attribute. This may be a disagreeable taste or a nauseous smell in the fluids and tissues of the larva, and perceived alter it has been bitten ; or it may be a strongly smelling fluid, discharged by certain special glands on the approach of an enemy (e. g. Porthesia auriflua with dorsal glands, or the Hymenopterous Croesus septentrionalis with ventral glands ; in both these cases the smell given off from the everted glands can be readily perceived as sharp or unpleasant to ourselves). The larvse oi Pieris brassicw, or of Pygara bueephala, &c, form instances of the former |