Wirenia argentea larvae and postlarvae (days 10-16), SEM micrographs. A. Day 10 larva in dorsolateral view with apical cap consisting of pretrochal cells, prototrochal cells (pro) characterized by cilia-free surface (arrowhead), and first tier of posttrochal cells (pt1); note that sclerites covering the posterior trunk are still partly covered with cuticle (double arrowhead); scale bar 30 μm. B. Day 12 larva in lateral view with fully developed postlarval sclerites; prototrochal cilia (pro), some cells of first tier of posttrochal cells (pt1) and telotroch (tt) still present; arrow marks foot; scale bar 30 μm. C. Day 16 larva in ventral view, telotroch and most of apical cap reduced; note a last prototrochal cell (arrowhead) and some compound cilia on the anterior body tip; arrows mark foot; scale bar 30 μm. D. Day 10 larva in an apical/ventral view showing ventral cleft between second tier posttrochal cells (pt2) exposing part of ciliary pit (cp); note that epidermal sclerites are still covered by cuticle (arrowheads); fc: foot cilia, pro: prototroch cilia, pt1: first tier posttrochal cells, tt: telotroch; scale bar 10 μm. E. Detail of C, epidermal sclerites flanking and partly obscuring foot cilia (fc); scale bar 10 μm.