. 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. Evolutio7i and Taxonoiny 79 of costa of the hind wings is preserved. This is well shown in Papilo (PI. II, 2). This vein has been observed and figured b)' many writers ; but it has alwaj's been considered a precostal {i. e., humeral) vein. But I believe it is essentially- different from the humeral vein or veins o
. 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. Evolutio7i and Taxonoiny 79 of costa of the hind wings is preserved. This is well shown in Papilo (PI. II, 2). This vein has been observed and figured b)' many writers ; but it has alwaj's been considered a precostal {i. e., humeral) vein. But I believe it is essentially- different from the humeral vein or veins of the Lasiocampid^. The hu- meral veins of this family of moths are secondary developments ; while the spur in the humeral angle of butterflies is a rem- nant of one of the primitive veins, the costa. In the hind wings of many moths a coalescence of subcosta and radius also takes place to a greater or less ex- tent. These two veins may be joined for a short distance, as in Packardia, (Fig. 16), or they may be merged in- to one for a consid- erable proportion of their length as in Megalopyge, (Fig. 25), and in theSesi- idse. Every degree of coalescence be- t w e e n these ex- tremes exist. It has been customary in cases like the last to consider the subcostal vein wanting ; but it is only necessary to count the branches of the principal veins to .see that all are present ; moreover, in most cases the two coalesced veins are separate for a short distance near the base. There are, however, forms in which the basal part of radius is wanting. This con- dition is brought about in this wa}-. First, something interferes with the growth of the basal part of radius, and this vein becomes weaker than the otli-. FiG. 22. — Thyredopteryx. Fig. 23.—Diagram of part of hind wing of Thyre- Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly r
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