574 Professor E. B. Poulton on Mr. Thayer's 
explanation may well be that it is advantageous to direct 
attention to the wings rather than the vital parts; but it 
is precisely in these groups that the black body, and some- 
times the head, are so often marked with white or red. A 
bright red or orange collar is found in several species. 
Furthermore, it must be remembered that the body being 
moved much less rapidly than the wings during flight is 
more easily seen. The black and white apical area of the 
fore-wing may help to conceal, as Mr. Thayer supposes, 
under certain conditions, but the numerous examples of 
injuries at this very spot, figured in Plates IX and XI of 
our Transactions for last year, strongly support the hypo- 
thesis that it is directive, and diverts the stroke of the 
attacking enemy from the body. 
Apart from the suggested interpretation of mimetic 
resemblance, which I believe to be untenable, Mr. Thayer's 
suggestions supplement and complete rather than oppose 
existing hypotheses. The words he uses of the wasp may 
in fact be employed of the skunk, and the well-known 
distasteful Rhopalocerous groups, etc. The colours may 
not be conspicuous to enemies at a great distance, “yet 
when seen they may well profit by the pattern’s recogniz- 
ability.” We have rather insisted on this latter fact and 
its advantage, and Mr. Thayer has done us good service 
in calling attention to the other aspect of the appearance. 
Ideas not dissimilar to those of Mr. Thayer’s upon 
warning colours have for some time crossed my mind. 
Thus last year I suggested as regards the abundant, much- 
mimicked Limnas chrysippus, that its desert form dorippus 
(klugit) “is a development in a procryptic direction in areas 
where the struggle” is especially severe (Trans. Ent. Soc. 
Lond., 1902, p. 475). 
Furthermore, the idea has often forced itself upon me 
that the ground colour of the type form of this butterfly, as 
well as of the Ethiopian Acrzinx and Lycid beetles, may, 
under certain conditions and at a certain distance, become 
procryptic against the prevalent reddish tinge of the soil 
of Africa. 
The author’s suggestions of the resemblance of butterfly 
patterns in general to flower-masses and the shadow-depths 
between them; of the under-sides of Grapta and the 
upper-sides of many moths representing dead leaves lying 
on the ground and casting such shadows as they would 
throw at their small distance from it ; of the concealing 
