Fig. 2. Longitudinal thin sections through actin bundles in bristles of 54-hour pupae. These sections were selected because they show junctions between adjacent modules. If this plate is rotated 90° so the viewer is looking across the bundles, the 12-nm period owing to the fascin crosslinks can be easily recognized. This period is indicated by the bars in (b) and (c), but it is especially visible near the base of each micrograph. If the bristle is bent before fixation, the overlap between adjacent modules separates at the point of overlap (a). As the module shortens, the number of filaments found in the overlap region decreases (b). Shortly thereafter a distinct gap is seen between adjacent modules (c).