Zaitzevia yaeyamana Satô, 1963 (Figs 2B, 12, 19C) Materials examined. JAPAN: [RYUKYU]: 11 larvae, Miyara-gawa, Hirae, Ishigaki-shi, Okinawa Pref., Ishigakijima, Ryukyu, 1.ii.2011, Y. Kamite leg. 4 larvae, Aira-gawa, Komi, Taketomi-chô, Okinawa Pref., Iriomote-jima, Ryukyu, 4.iii.2018, Y. Ishida & R. Morimoto leg. 1 larva, Aira-gawa, Taketomi-cho, Iriomotejima, 7.vi.2014, Y. Kamite leg. Description. Body length of mature larva ca. 4.0 mm in expanded specimen. Body elongate, narrowing from thorax to apex; convex dorsally and flattened ventrally; semicircular in cross section; spiracles on mesothorax and abdominal segments I–VIII. Body color black or dark brown, and appendages orange colored. Dorsal and ventral surfaces entirely not smooth with flat granules (Fig.12D; Kodada et al. 2016: 583) and various types of setae. Head visible from above, well exposed from prothorax; as wide as long; clypeus transverse, setose; without a pair of spines on both sides of clypeus (frontal tooth); vertex rugose with brush-like setae; eyes large but lens of stemmata absent. Antenna with three antennomeres; antennomere 1 shorter than antennomere 2, with short branched setae; antennomere 2 with long sensorial appendage; antennomere 3 short with small sensorial appendage. Maxillae and labium forming a unit (maxillolabial unit). Maxilla with three palpomeres; cardo small; stipes large; galea and lacinia separate, setose apically. Labium narrow with two palpomeres; ligula short and transverse; mentum long; submentum short and transverse. Thorax not serrated on lateral sides; dorsum entirely not smooth with granules and flat brush-like setae (Fig. 19C). Prothorax wider than long, 2 times as long as mesothorax; with glabrous smooth area on dorsum; with seven ventral sclerites (one between coxae, two anteromedial, two anterolateral, and two posterolateral), procoxae not closed posteriorly; flat feather-like setae on hind margins. Meso- and metathorax transverse; metathorax slightly longer than mesothorax. Meso- and metathorax with five ventral sclerites (one large anteromedial, two anterolateral, and two posterolateral). Abdomen 9-segmented; segments I–VIII transverse, dorsal surface entirely not smooth with granules; pleural sclerites on segments I–VII. Last segment (segment IX) longer than wide, gradually narrowing to apex; tergal surface with minute and coarse granules; with ridge on both sides (Fig. 12E); with longitudinal ridge on meson; apex notched; ventrally flat, with subpentagonal-shaped operculum, opercular claws, and anal gills. Habitat. Middle to upper stream reaches; larvae live in the gravel substrate. Identification. The larva was identified by association with adult Z. yaeyamana from Aira-gawa, Iriomote-jima Island. The larva was easily distinguished from Z. aritai by body coloration. Distribution. Yaeyama Isls: Iriomote-jima Is., Ishigaki-jima Is. (type locality). Bibliography. The larva of this species is described here for the first time.

Published as part of Hayashi, Masakazu & Kamite, Yuuki, 2020, Description of larvae of Japanese Macronychini (Coleoptera: Elmidae: Elminae), pp. 195-227 in Zootaxa 4859 (2) on page 222, DOI: 10.11646/zootaxa.4859.2.2, http://zenodo.org/record/4412885