A text-book of entomology, including the anatomy, physiology, embryology and metamorphoses of insects, for use in agricultural and technical schools and colleges as well as by the working entomologist . s is slightly variable. We have designated the abdomen as the urosome; the abdominal segmentsof insects and other Arthropods as uromeres. and the sternal sclerites as uro-vtirnites, farther condensed into urites. (See Third Report U. S. EntomologicalCommission, 1883, pp. 307, 324, 4:)o, etc.) The reduction takes place at the end of the abdomen, and isusually correlated with the presence or abse
A text-book of entomology, including the anatomy, physiology, embryology and metamorphoses of insects, for use in agricultural and technical schools and colleges as well as by the working entomologist . s is slightly variable. We have designated the abdomen as the urosome; the abdominal segmentsof insects and other Arthropods as uromeres. and the sternal sclerites as uro-vtirnites, farther condensed into urites. (See Third Report U. S. EntomologicalCommission, 1883, pp. 307, 324, 4:)o, etc.) The reduction takes place at the end of the abdomen, and isusually correlated with the presence or absence of the the more generalized insects, as the cockroaches, the tenth seg-ment is, in the female, com-pletely aborted, the ventralplate being atrophied, whilethe dorsal plate is fused dur-ing embryonic life, as Cholod-kovsky has shown, with theninth tergite, thus formingthe suranal plate. In the advanced nymph ofPsylla the hinder segments ofthe abdomen appear to be fusedtogether, the traces of segmenta-tion being obliterated, though thesegments are free in the first stageand in the imago (Fig. 178). Itthus recalls the abdomen ofspiders, of Limulus, and the pygi-dium of FIG. 178. —Nymph of the pear tree Psylla, with itsglandular hairs.—After Slingerland. Bull. Div. S. Dep. Agr. The median segment. — There has been in the past much discussionas to the nature of the first abdominal segment, which, in thoseHymenoptera exclusive of the phytophagous families, forms a partof the thorax, so that the latter in reality consists of four segments,what appearing to be the first abdominal segment being in realitythe second. Latreille and also Audouin considered it as the basal segment of the abdo-men, the former calling it the segment m6diaire, while Newman termed itthe propodeum. This view was afterward held by Newport, Schiodte, Rein-hard, and by the writer, as well as Osten Sacken, Brauer, and others. Thefirst author to attempt to prove this by a s
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectinsects
