Stage 21, Petiolus. All scale bars 200 μm. Light micrograph, a; Sytox staining, a', a''; SEMs, b-d. a: Lateral view. A narrowing region (petiolus) connects the prosoma (Pro) and opisthosoma (Op). The colour of the opisthosoma is distinct from the prosoma due to the large proportion of yolk (Y) a': Lateral view of same embryo as in a. The prosomal shield (PS) is clearly evident, as are the differentiating spinnerets (Sp). a'': Ventral view, same embryo as in a and a'. The lobes of the spinnerets (Sp) and anal tubercle (AT) are prominent. b: Lateral view. c: Ventral view. d: Dorsal view. The SEMs of b, c and d show that the swollen opisthosoma is connected to the prosoma by a narrowing petiolus (Pet). The appendages are long and segmented, and the prosomal shield (PS) is prominent. Due to a cuticle cover (torn edges evident in c), the opisthosomal surface shows little indication in SEM images of the spinnerets that are evident with Sytox staining in a''. Ch, chelicere; L1-L4, walking legs one to four; X, damaged area, cuticle torn.