Fig. 9. Cytochalasin promotes the premature breakdown of modules into subbundles. Macrochaetes from wild-type thoraces cultured in the presence of cytochalasin (35-42 hours) were fixed, stained with rhodamine-labeled phalloidin and imaged by confocal microscopy. Panel (b) shows an increased number of bundles in the bristle shaft (arrowhead). The modules seem to dissolve into subbundles at the base of the shaft (arrow) and accumulate in the cell body. Panel (a) shows a higher magnification of the extra bundles present in a different bristle. Panel (c) shows another bristle and what appear to be subbundles pouring off the end of the bristle shaft (arrow) and into the cell body. Bars, 5 µm.