Fig. 3. Two rounds of endoreplication occurred in the socket and the shaft cells. Staining of nota from A101 pupae between 21 hours 30 minutes and 30 hours APF (A-D). ß-Gal staining is in green, BrdU detection in red and Su(H) in blue. During this period, BrdU, when incorporated, was located in the shaft and/or the socket cells. Four types of clusters were observed: clusters with no BrdU labelling (A); clusters in which the shaft cell incorporated BrdU (B); clusters in which the socket cell incorporated BrdU (C); and clusters in which both the shaft and socket cells incorporated BrdU (D). (E) Histogram showing the percentage of clusters harbouring a BrdU-labelled shaft cell (black bars) or a BrdU-labelled socket cell (white bars) as a function of time after pupal formation. Note the bimodal distribution for each cell. Bars were calculated after analysis of 25 clusters. Scale bar: 2 µm. n, neuron; s, sheath cell; sh, shaft cell; so, socket cell.