forest-pictures, until its disturber comes within a few feet or even inches of it, 

 when it expands them suddenly and goes flashing off through the forest, only 

 to repeat the trick. This kind of 'dazzling' is doubtless a frequent factor, 

 of greater or less relative importance, in the disguising coloration of butter- 

 flies, and also of moths, which we shall presently consider in some detail. 



Lesser iridescence — the soft, masking sheen of bright, or especially of 

 dusky, markings, is common to a vast majority of butterflies— as, indeed, of 

 highly patterned animals of all classes. Its obliterative effect is constant and 

 essential. Such lustre of dusky markings in a butterfly's picture-pattern is 

 frequently offset by a complete sheenlessness of the accompanying light-col- 

 ored stripes or spots, and this combination is potent to 'obliterate.' For the 

 dark parts, with their ever-varying play of soft rainbow-sequences of tint, 

 together form, as it were, a sort of fluid medium, a positionless, mutable at- 

 mosphere, in which are suspended the definite and sharp details of the pic- 

 ture-patterns, with their fixed positions. Or, to express it still more figura- 

 tively, the butterfly has first been converted into space, and then that space 

 furnished with such material details as it should normally contain. Not 

 merely among butterflies, but throughout the animal kingdom, such minor 

 lustrousness is a common and important factor of obliterative pattern. A 

 perception of its use is indispensable to a full understanding of obliterative 

 coloration. 



So far we have considered butterflies' patterns chiefly with regard to their 

 ultimate effects of 'background-picturing.' We must now examine more 

 particularly the principles which underlie these effects, the principles of the 

 intrinsic ' obliterativeness ' of patterns. These have been touched on in our 

 earlier chapters, but since many of them show up in much clearer application 

 in the costumes of butterflies than in those of any other animals, they shall 

 here be described anew. The term 'dazzling coloration,' in its widest 

 sense, might include them almost all, for they almost all deal with devices 

 and systems of devices for the reduction of one form's or detail's conspicu- 

 ousness by the blazoning of some other detail. The butterfly's organic form 



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