. Occasional papers of the California Academy of Sciences. ors, the apices of suchrelatively stiff wings must have frequently snaggedagainst opposing gallery walls and slowed or prevent-ed escape. To overcome such a problem, and to in-crease suppleness during U-turns, embiids long agoevolved extraordinary wing flexibility. As a result,when in repose over the back, the wings of all mod- ern embiids readily fold transversely and slide for-ward toward the head (Fig. 23), thereby reducinglikelihood of a snag, or barb-effect. Although the wings usually fold upward andcephalad across their midline,
. Occasional papers of the California Academy of Sciences. ors, the apices of suchrelatively stiff wings must have frequently snaggedagainst opposing gallery walls and slowed or prevent-ed escape. To overcome such a problem, and to in-crease suppleness during U-turns, embiids long agoevolved extraordinary wing flexibility. As a result,when in repose over the back, the wings of all mod- ern embiids readily fold transversely and slide for-ward toward the head (Fig. 23), thereby reducinglikelihood of a snag, or barb-effect. Although the wings usually fold upward andcephalad across their midline, they can bend at al-most any point and may even irregularly flexibility appears to have been accomplishedthrough desclerotization of most of the longitudinalveins behind the radial blood sinus (RBS), notablythe media (M) and cubitus (Cu). Perhaps reductionof plication is also involved, as suggested by the factthat vein cuticularization is almost entirely confinedto the dorsal membrane with only blood sinus veinsevident on both wing
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectscience, bookyear1890
