. Transactions of the Entomological Society of London. sheath has all the appearance in mostcases of being the outer layer of this portion of the aedeagusset free from the inner; a little further on, however, theyseem to be completely fused. Following them on, assuminghowever, that we are following the outer layer, we arriveat the internal opening of the aedeagus, where the onelayer is reflected into the other; and now returning on ourjourney, but following the inner layer, we arrive again atthe zone and pass on to the free external portion of theaedeagus, and reaching its extremity, return do
. Transactions of the Entomological Society of London. sheath has all the appearance in mostcases of being the outer layer of this portion of the aedeagusset free from the inner; a little further on, however, theyseem to be completely fused. Following them on, assuminghowever, that we are following the outer layer, we arriveat the internal opening of the aedeagus, where the onelayer is reflected into the other; and now returning on ourjourney, but following the inner layer, we arrive again atthe zone and pass on to the free external portion of theaedeagus, and reaching its extremity, return down itsinterior, along the ductus proper, in which there is nodefinite line of demarcation between the eversible portion Pairing of the Plebeiid Blue Butterflies. 163 (vesica, Pierce) and the more internal portion which isnever everted. In some species with longer external portions to theaedeagus (as in Thecla) there is, strictly speaking, noeversible membrane, the extremity of the aedeagus appearsto reach the bursa and there expands, by the spreading. Fig. 5.—A diagram to show the continuity of the azygos ductwith the cutaneous surface (floor of genital cavity). Thearrows indicate the route from the external surface by wayof the membranous sheath (sinus*), the surface so far, oftenbearing hairs, to the zone, thence, fused to its returning layer,to the internal opening of the aedeagus and back again, con-tinuing then as the external portion of the shaft of the aedeagus,and at its extremity returning as eversible membrane andductus. of portions of its extremity and stretching of the adjacentmembrane; this membrane and the movable portions atthe extremity of the aedeagus are, however, no doubt,homologous with the eversible membrane and cuneus(cornidi, Pierce). * Zander, Zeitsh. fur. Wiss. Zool. 1903, applies the term penis-lasche to the sleeve for which I have accepted the name sinus, butextends the said penis-lasche not only to the base of the aedeagusbut right away beyond the
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Keywords: ., bookauthorr, bookcentury1800, booksubjectentomology, bookyear1836
