Identifier: smithsonianmisce951937smit (find matches)
Title: Smithsonian miscellaneous collections
Year: 1862 (1860s)
Authors: Smithsonian Institution
Subjects: Science
Publisher: Washington : Smithsonian Institution
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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in length during subsequent instars. In the earlier stagesthe vasa deferentia open directly into the median tube, which thusappears in its inception to be the ductus ejaculatorius. A diphallic condition is said by Crampton (1918) to occur in Nemoura completa,but since the structures designated penes are not demonstrated tobe such by dissection, we may suspect that they are merely phalliclobes, and that a single genital orifice will be found between them. In the genus Leiictra the phallic apparatus is much reduced, andit appears that the intromittent function may be performed by a pairof processes arising from the sternum of the tenth abdominal segment.These structures are described by Klapaiek in L. nigra and cylindrica,and by Mertens in L. prima and hippopiis as a pair of scleroticprocesses (Chitingraten, Titillatoren) arising at the sides of the geni-tal orifice, and embraced by two prolongations of the plates of thetenth sternum. Each median process, according to these authors, is
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Fig. 29.—Hexapoda-Plecoptera: external genitalia. A, Acroncuria arida, male, end of abdomen, dorsal view. B, same, ventralview. C, Acroncuria^ female, end of abdomen, ventral view. D, Acroncuriaarida, male, end of abdomen, lateral view. E, Acron-curia evohita, end of abdomenwith protracted penis (from Clark, 1934). F, Neophasganophora capitata, endof abdomen, dorsal view (from Frison, 1935). G, Nemoura bifurcata, end ofabdomen, dorsal view. H, same, supra-anal process, lateral view. I, same,end of abdomen, ventral view. J, Pteronarcys proteus, end of abdomen, lateralview. K, Taeniopteryx nmura, end of abdomen, lateral view. L, Leuctra sibleyi,end of abdomen, lateral view. M, same, ninth and tenth abdominal segments,ventral view. a, tergal process of eighth abdominal segment; b, tergal process of ninth seg-ment ; c, percussion disc of ninth sternum; Cer, cercus; d, basal lobe of ninthsternum; c, lateral process of tenth segment; Eppt, epiproct; /, g, lateral andmedian ventral process

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