. The elements of insect anatomy; an outline for the use of students in entomological laboratories. Ill sideration have been developed. For additions to such a set of veins may be made to the distal end of the series, or to the proximal end, or may be interpolated at some distance from either end. We will illustrate these principles by a figure of the wing of a nymph of a cockroach (Fig. 10). We do not use for this purpose a figure of a wing of a'neuropterous insect, as that would lessen the value, as a means of training, of the study of neuropterous wings which the student is to make. A. FIG.
. The elements of insect anatomy; an outline for the use of students in entomological laboratories. Ill sideration have been developed. For additions to such a set of veins may be made to the distal end of the series, or to the proximal end, or may be interpolated at some distance from either end. We will illustrate these principles by a figure of the wing of a nymph of a cockroach (Fig. 10). We do not use for this purpose a figure of a wing of a'neuropterous insect, as that would lessen the value, as a means of training, of the study of neuropterous wings which the student is to make. A. FIG. 10.—Hind wing of a nymph of a cockroach. nymph is used here, because in the many-veined insects the longitudinal veins, both primitive and accessory, are devel- oped about tracheae ; and it is much easier to determine the homologies of the tracheae of an immature wing than it is to determine the homologies of the wing-veins of the adult. And, too, in this way we are able to eliminate the cross- veins which are not preceded by tracheae in the cockroaches. Accessory veins added distally.—If the radial trachea of tne nymph of a cockroach be examined (Fig. 10, R\ it will be seen that it bears many branches on its cephalic side ; each of these branches is enclosed by a vein in the adult state. The number of these veins is much gre'ater than that of the. 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 resemble the original Comstock, John Henry, 1849-1931. Ithaca, N. Y. , Comstock Pub. Co.
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