18.01.2013 Views

The Descent of Man

The Descent of Man

The Descent of Man

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

as generally occurs, to all <strong>of</strong> them." Mr. MacLachlan<br />

informs me <strong>of</strong> another instance <strong>of</strong><br />

dimorphism in several species <strong>of</strong> Agrion, in<br />

which some individuals are <strong>of</strong> an orange colour,<br />

and these are invariably females. This is<br />

probably a case <strong>of</strong> reversion; for in the true Libellulae,<br />

when the sexes differ in colour, the<br />

females are orange or yellow; so that supposing<br />

Agrion to be descended from some primordial<br />

form which resembled the typical Libellulae in<br />

its sexual characters, it would not be surprising<br />

that a tendency to vary in this manner should<br />

occur in the females alone.<br />

Although many dragon-flies are large, powerful,<br />

and fierce insects, the males have not been<br />

observed by Mr. MacLachlan to fight together,<br />

excepting, as he believes, in some <strong>of</strong> the smaller<br />

species <strong>of</strong> Agrion. In another group in this Order,<br />

namely, the Termites or white ants, both<br />

sexes at the time <strong>of</strong> swarming may be seen running<br />

about, "the male after the female, someti-

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

Saved successfully!

Ooh no, something went wrong!