18.01.2013 Views

The Descent of Man

The Descent of Man

The Descent of Man

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

engraved from a beautiful drawing, most kindly<br />

made for me by Mr. Trimen; see also his description<br />

<strong>of</strong> the wonderful amount <strong>of</strong> variation<br />

in the coloration and shape <strong>of</strong> the wings <strong>of</strong> this<br />

butterfly, in his 'Rhopalocera Africae Australis,'<br />

p. 186.) In cases like these, the development <strong>of</strong> a<br />

perfect ocellus does not require a long course <strong>of</strong><br />

variation and selection.<br />

With birds and many other animals, it seems to<br />

follow from the comparison <strong>of</strong> allied species<br />

that circular spots are <strong>of</strong>ten generated by the<br />

breaking up and contraction <strong>of</strong> stripes. In the<br />

Tragopan pheasant faint white lines in the female<br />

represent the beautiful white spots in the<br />

male (49. Jerdon, 'Birds <strong>of</strong> India,' vol. iii. p.<br />

517.); and something <strong>of</strong> the same kind may be<br />

observed in the two sexes <strong>of</strong> the Argus pheasant.<br />

However this may be, appearances strongly<br />

favour the belief that on the one hand, a<br />

dark spot is <strong>of</strong>ten formed by the colouring matter<br />

being drawn towards a central point from a

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!