. 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. 54 John Henry Comstock. Fig. 3.—Palceoblattina douvillei. We are not entirely without evidence that this is the method of the formation of wing veins. It will be shown later that when the principal .stem of one system of veins (media) is obliterated and the branches of this system are forced to derive their supply
. 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. 54 John Henry Comstock. Fig. 3.—Palceoblattina douvillei. We are not entirely without evidence that this is the method of the formation of wing veins. It will be shown later that when the principal .stem of one system of veins (media) is obliterated and the branches of this system are forced to derive their supply of air through lat- eral tracheae extending to adjacent .systems of veins, these lateral tracheae become enveloped by veins resembling in every respect the principal veins. Similar evidence may be drawn from the study of the development of the humeral veins in the Lasiocampidae. Since we are not able to determine the form and function of the organs which were modified into wings, let us endeavor to select the most generalized type of wings preserved to us. We will first see what light Palaeontology throws upon this ques- tion Comparatively little is known regarding the primitive in- sects. But thanks to the labors of Mr. S. H. Scudder, who has been one of the chief workers in this field, what is known has been made easily accessible.''' Winged insects apj>eared very early, probably as earl}' as any land plants ; for Moberg has figured an insect (in the Forhandlingar of the Swedish geological society) from the upper part of the lower silurian ; and Brongniart has figured and described a wing from the middle silurian sandstone of Calvados, France. (Fig. 3). But this wing instead of being primitive in form represents a rather highly specialized type, if the figure given correctly represents Fig. 4.— Honiothetus fossilis. *Zittle. Traite de Paleontologie t. II. Bull. U. S. Geol. Survey No. 31. Bull. U. S. Geol. Survey No. 69. Fossil Insects of North America. Vol. I. Pretert
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