The apterous expression pattern in the left haltere disc over time in flies expressing UAS CD8-GFP under the control of apGAL4.

<p>The haltere disc is indicated by the lighter area. <b>A:</b> first instar haltere disc, without ap expression. <b>B:</b> same haltere disc the next day (about 16(1) h after the first image (AFI)). The larva has entered the second instar and now shows expression of apterous. <b>C:</b> 24(1) h AFI. <b>D:</b> 40(1) h AFI. <b>E:</b> 48(1) h AFI. <b>F:</b> 64(1) h AFI. The larva is in the third instar. <b>G:</b> 72(1) h AFI. In this image it can be seen that the D/V boundary is not yet smooth. <b>H:</b> 88(1) h AFI. The D/V boundary is now smooth and well-defined. <b>I:</b> 96(1) h AFI. <b>J:</b> 112(1) h AFI. <b>K:</b> 120(1) h AFI. The scale bar is 50 µm in all images.