Figure 14
From: Structural aspects of leg-to-gonopod metamorphosis in male helminthomorph millipedes (Diplopoda)
O. gracilis male late stadium VII (pharate phase). Three sub-phases are distinguishable. (A-C) Fused EDF-stacks; lateral view. (D-F) Para-midsagittal paraffin sections; Mallory's triple stain. A and D, first step of the pharate phase: the gonopod primordium is formed by three parts, separated by two constrictions; in section only the epidermis is visible (arrowhead). B and E, second step of the pharate phase: an elongated structure is visible inside the detached cuticle of the gonopod primordium; the gonopod primordium contains a mass of tightly packaged cells, distally branched (arrow). C and F, third step of the pharate phase (see text): the distal processes of the gonopod telopodite are recognizable under the transparent old cuticle; branching of distal telopodite parts is very advanced (arrows). Anterior to the left, scale bars 100 μm.