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APE'S HILL 204 APHRODITE length, thus rendering these instruments exceedingly convenient for use. Sir W. Herschel's 18-inch metallic speculum, used for examining the nebulae and Milky Way, had a focal length of 20 feet; modei-n telescopes, with silvered-glass mirrors, have been constructed of the same aperture, but with a focal length of not more than seven feet. Angular aperture (in microscopes), the amount of light transmitted by the objective, and, consequently, the distinct- ness of the image afterward magnified by the lenses forming the eye piece. When an objective of the large angular .perture is employed, the more delicate .narkings of the object utider examina- tion, invisible when objectives of less angular aperture are used, are seen with great distinctness. APE'S HILL (Arabic, Jebel Zatus), the ancient Abyla, the extremity of a mountain range in the N. of Morocco, opposite Gibraltar; one of the "Pillars of Hercules." APHANIPTERA (af-an-ip'ter-a) , an order of wingless insects, called by De Geer suctoria, and by Leach siphonap- tera. They have a sucker of three pieces, and a true metamorphosis. The thorax is distinctly separated from the abdomen, and two horny plates mark the spots where in the higher insects wings would be. It contains the pulicidse, or fleas. APHASIA, in pathology, a symptom of certain morbid conditions of the nervous system, in which the patient loses the power of expressing ideas by means of words, or loses the appropriate use of words, the vocal organs the while re- maining intact and the _ intelligence sound. In one form of the disease, called aphemia, the patient can think and write, but cannot speak; in another, called agra- phia, he can think and speak, but cannot express his ideas in writing. The treat- ment is that of the underlying disease. APHELION, that part of the orbit of the earth or any other planet in which it is at the point remotest from the sun. APHIS (a'fis), a genus of insects, the typical one of the family aphidx. It contains those soft pulpy little animals, winged or wingless, and with long anten- nae, which are seen beneath the leaves, or in curled-up leaves, or in the axils of many plants, or even on the roots of some. Sometimes, as in the case of the elm, their destructive operations upon a leaf raise a gall of considerable size. The species are very numerous, and are gen- rally called after the plants on which they feed, as A. rosse, the aphis of the rose; A. fahse, the bean aphis; A. brassicae, the cabbage fly; A. humuli, the hopfly. They are exceedingly prolific, but are kept within bounds by various insects, especially by the coccinellidse, or lady birds, of which they are the ap- propriate food. They drop a fluid called honey-dew, which is so grateful to the ants that the latter, to receive it, tend them like milch cows. The mode of propa- gating their race is the abnormal one described as alternation of generations, metagenesis, and parthenogenesis. The winged aphides, confessedly perfect in- sects, bring forth a wingless race, apparently mere larvae, and which there- fore, it might be thought, would be in- capable, while thus immature, of bring- ing forth young. In certain cases they do it, however, and their offspring are winged, and as perfect as their grand- parents. This alternation of genera- tions, or metagenesis, with its attendant parthenogenesis (or birth from virgins) in every second generation, goes on for nine or ten generations by which time the season is over. The last aphides of the year are fully formed and winged, and deposit eggs, which are hatched in spring. APHONIA, in pathology, the greater or less impairment, or the complete loss of the power of emitting vocal sound. The slightest and less permanent forms often arise from extreme nervousness, fright, and hysteria. Slight forms of structural aphonia are of a catarrhal nature, resulting from more or less con- gestion and tumefaction of the mucous and sub-mucous tissues of the larynx and adjoining parts. APHRODITE (af-ro-dl'te) , one of the chief divinities of the Greeks, the goddess of love and beauty, so called be- cause she was sprung from the foam aphros of the sea. She was the wife of Hephjestus, but she loved besides, among gods. Ares and Dionysus, and among mortals, Anchises and Adonis. The chief places of her worship in Greece were Cyprus and Cythera. In earlier times the patroness of marriage and maternity, she became later the ideal of graceful womanhood, and was spiritu- alized by Plato as Aphrodite Urania. By others she was degraded in Aphrodite Pandemos to be the patroness of mere sensual love. The worship of Aphrodite was originally the symbol of the fructify- ing powers of nature. Her cult was introduced by the Phoenicians into Cy- prus, and soon spread over all Greece. She was originally identical with As- tarte, the Ashtoreth of the Hebrews. By the Romans she was identified with