Figure 15

Regular pattern of air sacs (AS) and hemolymph channels (H) that result from developmental processes like those described herein. First instar, Centruroides gracilis. TEM. There is a thin epithelial layer (E) attached to the hemolymph surface of the air sacs. The hemolymph channels (H) still have some cell debris, but are nearly open for passage of fluid. Evident are many bridging trabeculae (BT) that extend between the air sac walls. These space holders apparently result from the fusion of smaller cuticle-enclosed compartments (Figs. 12, 13) or extension of cell processes (Fig. 14) and trabeculae (asterisks) into the lumen of the developing air sacs. The air sacs here are ~1.5 μm wide while the hemolymph channels are 5-7 μm wide. Scale, 5 μm.