In both genera the spots arise at first locally on one or two segments, from which they are transferred to the others as a secondary character. In _Chærocampa_ this transference is chiefly backwards, in _Deilephila_ invariably forwards. We have now to inquire whether complete eye-spots--such as those of the _Chærocampa_ larvæ--have any significance at all, and whether they are of biological importance. It is clear at starting, that these spots do not belong to that class of markings which make their possessors more difficult of detection; they have rather the opposite effect. We might thus be disposed to class ocellated caterpillars with those “brightly coloured” species which, like the _Heliconinæ_ and _Danainæ_ among butterflies, possess a disgusting taste, and which to a certain extent bear the signal of their distastefulness in their brilliant colours. But even if I had not found by experiment that our native _Chærocampa_ larvæ were devoured by birds and lizards, and that they are not therefore distasteful to these insect persecutors, from the circumstance that these caterpillars are all protectively coloured, it could have been inferred that they do not belong to this category. It has been found that all adaptively coloured caterpillars are eaten, and one and the same species cannot possibly be at the same time inconspicuously (adaptively) and conspicuously coloured; the one condition excludes the other. What other significance can eye-spots possess than that of making the insects conspicuous? Had we to deal with sexually mature forms, we should, in the first place, think of the action of sexual selection, and should regard these spots as objects of taste, like the ocelli on the feathers of the peacock and argus-pheasant. But we are here concerned with larvæ, and sexual selection is thus excluded. The eye-spots must therefore possess some other significance, or else they are of no importance at all to the life of the insect, and are purely “morphological characters;” in which case, supposing this could be proved, they would owe their existence exclusively to forces innate in the organism itself--a view which very closely approaches the admission of a phyletic vital force. I am of opinion, however, that eye-spots certainly possess a biological value as a means of terrifying--they belong to that numerous class of characters which occur in the most diverse groups of animals, and which serve the purpose of making their possessors appear as alarming as possible.