A field guide to the butterflies of africa by John George Williams

By John George Williams

Show description

Read Online or Download A field guide to the butterflies of africa PDF

Best science & math books

Modern Plasma Physics,

This three-volume sequence provides the guidelines, versions and ways necessary to figuring out plasma dynamics and self-organization for researchers and graduate scholars in plasma physics, managed fusion and comparable fields similar to plasma astrophysics. quantity I develops the actual kinetics of plasma turbulence via a spotlight on quasi-particle types and dynamics.

The illustrated encyclopedia of suculents

A consultant to typical background and cultivation of cacti and cactus- like crops. it's a nice ebook should you are searhing for extra clinical details on succulents households. It has many nice photographs, yet normally of the crops in typical habitat, that's very various from the "house vegetation" glance.

Additional info for A field guide to the butterflies of africa

Sample text

Translat. vol. ii. p. 939. See also Mr. H. Spencer's interesting speculations on the same subject, and on the genesis of nerves, in his ' Principles of Biology,' vol. ii'. p. 316 ; and in his ' Principles of Psychology,' 2nd edit. pp. 511-557. CHAP. I. SERVICEABLE ASSOCIATED HABITS. 31 cases with mankind in the inheritance of tricks or unusual gestures, to which we shall presently recur. To those who admit the gradual evolution of species, a most striking instance of the perfection with which the most difficult consensual movements can be transmitted, is afforded by the humming-bird Sphinx-moth (Macroglossa); for this moth, shortly after its emergence from the cocoon, as shown by the bloom on its unruffled scales, may be seen poised stationary in the air, with its long hair-like proboscis uncurled and inserted into the minute orifices of flowers; and no one, I believe, has ever seen this moth learning to perform its difficult task, which requires such unerringaim.

40 THE FKINCIPLE OF CHAP. I. this'is an habitual and not a strictly reflex action, as the stimulus is conveyed through the mind and not by the excitement of a peripheral nerve. The whole body and head are generally at the same time drawn suddenly backwards. These latter movements, however, can be prevented, if the danger does not appear to the imagination imminent; but our reason telling us that there is no danger does not suffice. I may mention a trifling fact, illustrating this point, and which at the time amused me.

In most of the foregoing cases, we can understand how the associated movements were acquired through habit; but with some individuals, certain strange gestures or tricks have arisen in association with certain states of the mind, owing to wholly inexplicable causes, and are undoubtedly inherited. 8 7 ' Me'canisme de la Physionomie Humaine,' 1862, p. 17. 'The Variation of Animals and Plants under Domestication,' vol. ii. p. 6. The inheritance of habitual gestures is so important for us, that I gladly avail myself of Mr.

Download PDF sample

Rated 4.90 of 5 – based on 32 votes