Smithsonian miscellaneous collections . Fig. 34.—Hypothetical type of primitive frenate hind wing. divides, giving rise to radius-two-plus-three and radius-four-plus-five. Each of these again divides into two branches, radius-two-plus-three into radius-two and radius-three; radius-four-plus-five intoradius-four and radius-five. Thus the vein ultimately becomes fivebranched. headlee] a study in butterfly wing-venation 287 My own studies have convinced me that this primitive type ofradius prevails among the most generalized lepidoptera such asHepialus, Sthenopis, and Castnia cochrus. Spuler also
Smithsonian miscellaneous collections . Fig. 34.—Hypothetical type of primitive frenate hind wing. divides, giving rise to radius-two-plus-three and radius-four-plus-five. Each of these again divides into two branches, radius-two-plus-three into radius-two and radius-three; radius-four-plus-five intoradius-four and radius-five. Thus the vein ultimately becomes fivebranched. headlee] a study in butterfly wing-venation 287 My own studies have convinced me that this primitive type ofradius prevails among the most generalized lepidoptera such asHepialus, Sthenopis, and Castnia cochrus. Spuler also evidentlyconsidered this type the most primitive in the Lepidoptera, for hefigured this exact condition in his Schema des Vorderfliigelgeadersder Schmetterlinge ^ (pi. lx, figs. 1-5 and 11). Thisj then, being the prevailing condition of radius not only in themost generalized lepidopterous wings but also in generalized insect. 3d A, Fig. 35.—Hypothetical type of primitive rhopalocerous fore wing. wings generally, as was shown by Comstock and Needham, maysafely be laid down as the primitive lepidopterous radius from whichthe present types have been developed. Usually the modificationstake the form of a coalescence between the radial branches, or of amore or less complete atrophy of individual branches. In fact,these are the means by which the heterocerous radius has been modi-fied. The rhopalocerous radius, on the other hand, shows not onlythe effects of such modifications but of a splitting back of 7^4+5 untilit finally comes to arise near the base of the main stem of radius(text fig. 35). The traces of the last appear in the adult wing ofAnosia plexippus in the form of two spurs and a connecting of the spurs is very short and projects from the base of radiusinto the discal cell and toward the outer edge of the wing, the otherprojects from the base of M-^^ into the discal cell and toward the base
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