. The Wilder quarter-century book: a collection of original papers dedicated to Professor Burt Green Wilder at the close of his 25th year of service in Cornell University (1868-1893). Wilder, Burt G. (Burt Green), 1841-1925; Zoology; Anatomy; Physiology; Evolution; African Americans. Evolution and Taxono->ny 8i 111 the hind wings of all Lepidoptera, except Hepialis (Fig. 27) and Micropteryx (Fig. 28), all of the branches of radius are united into one. But the condition of radius in the two genera named shows that it is normally five-branched in the hind wings as well as in the fore wings. I
. The Wilder quarter-century book: a collection of original papers dedicated to Professor Burt Green Wilder at the close of his 25th year of service in Cornell University (1868-1893). Wilder, Burt G. (Burt Green), 1841-1925; Zoology; Anatomy; Physiology; Evolution; African Americans. Evolution and Taxono->ny 8i 111 the hind wings of all Lepidoptera, except Hepialis (Fig. 27) and Micropteryx (Fig. 28), all of the branches of radius are united into one. But the condition of radius in the two genera named shows that it is normally five-branched in the hind wings as well as in the fore wings. In the discussion of media, given on a previous page, atten- tion was caUed, so far as concerns its coalescence with other veins, merely to its branches ; but the principal stem of this vein may become joined either to radius, as in the fore wing of Castnia (Fig. 15), or to cubitus, as in the fore wing of Prionoxyslus (Fig. 12). It will be observed that here is a character which is of value as indicating a dichotomous division of the line of descent. I do not recall any instance where cubitus is coalesced with an anal vein to a marked degree, except in the Papilionidse (PI. II, Fig. 2) ; but the growing together of dif- ferent anal veins is a very common occur- rence. This condition is preceded ph3dogenet- ically by the formation of a cross vein. Such a vein exists between veins IX and XI of the fore wings of Castjiia (Fig. 15), and between veins VIII and IX of Thyridopteryx (Fig. 22). Following this stage the two veins are drawn to- gether, See veins IX and XI of the fore wings of Thyridopteryx (Fig. 22), and the same veins \x\ Megalopyge (Fig. 25). Usually, however, when these veins are joined in this way, that part of vein XI beyond the point of union disappears, and vein IX presents the appearance of being forked towards the base. See Adoneta (Fig. 17).. IX viu Fig. 25.— Please note that these images are extracted from scanned page images that may have been dig
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