. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. MECHANICS OF FLIGHT IN DIPTERA 205 somewhat independent movement of these two structures, a fact which is important in the production of the basic movement cycle. As noted above, contraction of either the longitudinal or the vertical muscles will produce lateral expansion of the thorax at point f. This force is transmitted to the articulation by the anterior notal process. In Figure 3 (A and B) the con- nection between the main part of the notum and the articulation is shown. The existence of the flexible hinge connection (h
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. MECHANICS OF FLIGHT IN DIPTERA 205 somewhat independent movement of these two structures, a fact which is important in the production of the basic movement cycle. As noted above, contraction of either the longitudinal or the vertical muscles will produce lateral expansion of the thorax at point f. This force is transmitted to the articulation by the anterior notal process. In Figure 3 (A and B) the con- nection between the main part of the notum and the articulation is shown. The existence of the flexible hinge connection (h), not previously described, makes the presently accepted theory of the cause of the down movement of the wings highly. B FIGURE 3. Cross sectional view of thorax showing details of the articulation of the right wing. A. Wing in up position, anterior view. B. Wing in the down position, anterior view. C. Posterior view of the axillary sclerites of right wing showing their relation to the mesopleural process, the lever arm and the anterior parascutum. a, mesopleural process; b, pleural apophysis; c, anterior pleurosternal muscle; d, anterior parascutum; e, first axillary sclerite; f, second axillary sclerite; g, base of radial vein; h, hinge; i, radial vein; j, hook articulation; k, point of articulation of anterior notal process, first axillary sclerite, base of radial vein and second axillary sclerite; 1, end of the lever arm. unlikely. Lateral expansion of the notum cannot possibly move the articulation from position shown in Figure 3A to that in Figure 3B as this theory predicts. Expansion of the notum, laterally, would move the hinge outward. However, due to rotation occurring at the hinge, the anterior notal process would not be moved out or up and the wing would remain in the up position (see Fig. 3). Through the anterior notal process the lateral force is focused on the wing articulation. The change in direction of this force necessary to wing movement is produced not by
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
