The British Noctuæ, Vol. 3
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Produktbeschreibung
Excerpt from The British Noctuæ, Vol. 3: And Their Varieties It must have been noticed by those lepidopterists who have read the previous volumes of this work that I have repeatedly referred to species as being "sexually dimorphic," in other words, that certain sexes are to be readily distinguished by some characteristic trait which is generally evident even on a superficial examination. Throughout the animal kingdom, there are a large number of species, the sex of which can be determined readily, apart from the sexual organs, by some external structure or conformation which strikes the most casual observer. On the other hand, there are species which have no outward visible signs of their sex, which can be determined alone by the special sexual organs with which most animals are provided. Lepidoptera are not behind-hand in this respect, and there are many external characters by means of one or more of which the sexes may be definitely distinguished without the examination of the sexual organs. These external signs of sex have been termed "secondary sexual characters." To these secondary sexual characters the term "antigeny" is applied by Scudder, and comprises all "those accessory peculiarities of either sex which are not directly connected with generation." Of these characters in lepidoptera we find a large variety. In fact, in some species or other almost any portion of the body may be so modified as to become such, and thus we find the antennæ, legs, thoracic crests, abdominal crests, the wings as a whole, the nervures, etc., all modified in particular species so as to become "secondary sexual characters," whilst wing markings and colour are also in many instances requisitioned for the purpose. Darwin in his "Descent of Man" has treated the subject of "secondary sexual characters" very fully, and Geddes and Thompson write: - "Among invertebrates prominent secondary sexual characters are rarely exhibited outside the great division of jointed-footed animals or arthropods. There, however, among crustaceans and spiders, but especially among insects, beautiful illustrations abound. Thus the great claws of crabs are frequently much larger in the males; and male spiders often differ from their fiercely coy mates, in smaller size, darker colours, and sometimes in the power of producing rasping sounds. Among insects, the males are frequently distinguished by brighter colours attractively displayed, by weapons utilised in disposing of their rivals, and by the exclusive possession of the power of noisy love-calling. Thus, as the Greek observed, the Cicadas "live happy, having voiceless wives." Not a few male butterflies are preeminently more beautiful than the females; and many male beetles fight savagely for the possession of their mates" (´Evolution of sex,´ p. 6). About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
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