Fig. 2

Morphological and histological transitions during nymphal instars in Z. nevadensis (a–i) and H. sjostedti (j–r). Developmental processes of nymphal instars are divided into three stages: N1 (first-instar nymph; a, d, g), N2E (early second-instar nymph; b, e, h) and N2L (late second-instar nymph; c, f, i) in Z. nevadensis; and NE (early nymph; j, m, p), NM (mid-nymph; k, n, q), and NL (late nymph; l, o, r) in H. sjostedti. Arrowheads indicate epithelial tissues of developing wings. All scale bars indicate 500 µm