Smicridea (Rhyacophylax) dithyra Flint 1974

(Figs. 14–18)

Smicridea (Rhyacophylax) dithyra Flint 1974a: 42 . Flint et al. 1999.

Description

Larva. Length: 7.9 to 11.7 mm (n=8). Head capsule greenish brown, with anterior margin of frontoclypeal apotome darker, and pale (yellowish) zones around stemmata, contrasting with coloration of other structures (Fig. 14). Transverse posterior band and lateral longitudinal band somewhat lighter than rest of head. Anterior margin of frontoclypeal apotome symmetrical, crenulate in middle, and with 2 slightly insinuated lateral notches; median depression marked (Fig. 14). Parietal apotomes with pale muscle scars, distributed characteristically as in Figs. 14–15. Lateral muscle scars similar to those of S. (S.) annulicornis . Without posterior ventral apotome. Distribution of muscle scars on pro­, meso­ and metanota as in Fig. 16. Poststernal sclerites of prosternum lacking. Mesosternum with 2 posterolateral subtriangular sclerites. Abdominal sternum VIII with 2 triangular sclerites bearing setae.

Pupa. Length: 7.7 mm (n=5). Anterior margin of labrum rounded, with row of long setae along it, and shorter setae covering anterior median region; lateral lobes with 4 to 5 long setae (Fig. 17). Mandibles similar to those of S. (S.) annulicornis . Abdominal plates IIa, IIIa, IIIp, IVa, Va and VIa wider than long; plates IVp, VIIa and VIIIa longer than wide. Anterior plates of abdominal segments III to VIII with large teeth on posterior margin, and small secondary teeth; plate IIa without secondary teeth; plate IIIp with large teeth along anterior margin and secondary small teeth; posterior border of plate IVp bending, directed forward, with large marginal teeth (Fig. 18).

Material examined

ARGENTINA: San Luis Province: Río El Volcán, 18.xii.2001, 4 larvae, 2 pharate females, 2 pharate males; Dique Chico, xii.2001, 4 larvae, 5 pupae, 1 pharate female, 1 pharate male.

Distribution

Argentina new record (San Luis Province); Guatemala; Honduras; Mexico.