PROCRYPSIS COMBINED WITH AN APOSEME 207 



the cleft gape widely open, so that the brightly coloured 

 spines are fully displayed. This may be seen in England 

 in the caterpillar of the " Lappet " moth. 



In the case of these caterpillars it must be remembered 

 that the presence of such an aposeme does not necessarily 

 imply that the caterpillar is intrinsically distasteful, but 

 that it possesses some unpleasant quality on account of 

 which it had better be left alone. I have a certain amount 

 of evidence that Hymenoptera, such as the stinging ants, 

 bees and wasps, are not avoided so much on account of 

 inedibility as on account of their powers of defence, which 

 they advertise by their conspicuous scheme of colouring, 

 or their habits. 



So that the combination of procrypsis with an aposeme 

 is not so inconsistent with the theory of natural selection 

 as it might appear to be at first. Another interesting 

 example of this combination is a fine large Noctuid moth, 

 abundant on the islands (Ophideres). It was usually first 

 seen on the wing after it had been disturbed from its 

 resting place, when its orange hind wings bordered with 

 black were very conspicuous. If it was followed up it 

 was seen to settle head downwards on the bark of a tree, 

 expose fully for a moment its orange hind wings, and then 

 suddenly close the wings with a snap and become invisible 

 owing to the mottled grey-green and brown tints of the 

 fore wings closely resembling the surface of the bark. 

 I am inclined to think that the conspicuous hind wings 

 are aposematic, else why should the moth take such pains 

 to display them for a moment, on alighting, before covering 

 them with the procryptic fore wings ? I suggest that the 

 moth endeavours to dissuade a pursuing enemy by freely 

 displaying its warning colours, and then settles and be- 

 comes invisible to any new enemy that had not seen it 

 when on the wing. 



On the other hand, it is possible that the colour of the 

 hind wings is of the nature of directive markings,^ which 

 * Colours of Anhnals, p. 204 et seq. 



