Figure 3

Details of the homeotically transformed appendages. A-D. The homeotic legs on A1 (B) and A4 (D) have a terminal claw like the control walking legs on T3 (A); the claws are marked with white arrows. Note the difference between (B) and the control collophore on A1 in (E), and between (D) and the tip of the control furca on A4 in (C). The two appendages forming the furca terminate with specialized structures (mucrones), marked here with black arrowheads; both appendages are shown. (E, F) The collophore on A3 (F) resembles the control collophore on A1 by its gross morphology and the presence of characteristic smooth cuticle at its tip (white arrowheads). (G, H) The homeotic furca on A3 has, like the control furca on A4, the proximal common manubrium (m) bifurcated into two distal dentes (d), although it is smaller (compare the scale bars). Most of the setae on the homeotic furca in (H) were lost during sample preparation. Note how the A3 homeotic appendages in (F) and (H) differ from the control retinaculum on A3 in (Figure 1D). Scale bars: in A, 20 μm for (A-D); in E, 20 μm for (E, F); (G) 100 μm; (F) 50 μm.