Entomology for beginners; for the use of young folks, fruitgrowers, farmers, and gardeners; . pring, as in the EuropeanPemphigus terebinthi (Derbes). Chermes and Phylloxera give birthin place of viviparous generations to a special egg-laying female,which also produces eggs, from which arise individuals which repro-duce parthenogenetically. In Phylloxera quercus, besides the twogenerations, there is another generation which appears in autumn, andconsists of very small males and females (without a suctorial proboscisor alimentary canal). These animals arise from two kinds of eggswhich are laid i
Entomology for beginners; for the use of young folks, fruitgrowers, farmers, and gardeners; . pring, as in the EuropeanPemphigus terebinthi (Derbes). Chermes and Phylloxera give birthin place of viviparous generations to a special egg-laying female,which also produces eggs, from which arise individuals which repro-duce parthenogenetically. In Phylloxera quercus, besides the twogenerations, there is another generation which appears in autumn, andconsists of very small males and females (without a suctorial proboscisor alimentary canal). These animals arise from two kinds of eggswhich are laid in the roots. The female after pairing lays only asingle egg. It is the same with the Phylloxera of the vine (Glaus).Of the latter there are two forms, one living in galls on the leaves, andthe other forming small swellings on the roots. The root-form iseither wingless or winged, the latter very rare. The leaf-form is saidto be always wingless. LEAF-HOPPERS. 81 Family Psyllidae.—These leaf-hoppers commonly live in all stageson the under surface of leaves, some of them forming galls. They. FIG. W.—Psylla tripunctata.—After Riley. are generally conical, with a broad head, with long, 10-jointed an-tennaj and short legs, the hinder ones adapted for springing; the
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectinsects
