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INHS Bulletin vol. 12:4PDF


Title:The Zygoptera, or Damsel-Flies, of Illinois
Author(s):Forbes, Stephen Alfred
Abstract:The order Odonata includes all insects known as dragon-flies in the broad sense of the term. The adults are characterized by the possession of four membranous, net-veined wings which are of nearly equal size. The mouth-parts are fitted for biting and the metamorphosis is incomplete. The males are distinguished by accessory genitalia on the second and third abdominal sterna. The nymphs are aquatic, and are recognizable and separable from other aquatic forms by the large hinge-like labium which folds beneath the head. The order is subdivided into two suborders, the Anisoptera and the Zygoptera. The adults of the Anisoptera have large, broad wings, but little contracted at the base and with numerous cross-veins. The wings of the Zygoptera are usually narrowed at the base and possess fewer cross-veins. The Anisoptera usually rest with wings spread horizontally; the Zygoptera usually with wings held vertically. The nymphs of the suborders are easily separated by means of the respiratory apparatus, the Zygoptera having three tracheal gills at the caudal end of the abdomen, and the Anisoptera having no caudal tracheal gills, being provided with rectal gills instead.
Issue Date:1917-06
Publisher:Champaign : Illinois Natural History Survey
Series/Report:Illinois Natural History Survey Bulletin; v. 012, no. 04
Publication Status:published or submitted for publication
Peer Reviewed:is peer reviewed
Rights Information:Copyright 2009 University of Illinois Board of Trustees. All rights reserved.
Date Available in IDEALS:2013-11-28

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