Isoperla mongolica Zhiltzova 1972

Teslenko, Valentina A. & Zhiltzova, Lidiya A., 2006, Nymphs of the genus Isoperla Banks (Plecoptera, Perlodidae) from the Eastern Palaearctic Region, Zootaxa 1130, pp. 1-33 : 20

Isoperla mongolica Zhiltzova 1972

( Figs.49–53 )

Description. Nymphs were correlated with adults according to theirs presents in collecting place in the same time. Length of mature male nymph 8.0–10.0 mm, female 10.0– 12.8 mm; cerci incomplete General body color pale­brown ( Fig. 49 ). Ventral body side yellowish.

Head with occipital spinule row interrupted medially; brown band between antennal bases; interocellar area pale and closed ( Fig. 49 ); pale spot anterior to anterior ocellus almost closed by thin transverse, dark stripe; lateral and anterior margins of frontoclypeus pale; labrum brown with small pale spot medially; occiput with dark, indistinct, and complicated banding and spotting. Lacinia bidentate ( Fig. 50 ), triangular, with slight subapical projection, inner lacinial margin with four stout setae and a row of 10–12 short thin setae below subapical projection; tip of galea reaches the subapical tooth base.

Thorax. Pronotum ( Fig. 49 ) fringed with short, thin setae, these prolonged on posterior pronotal margin; medial stripe pale except for short, dark band medially; lateral margins pale, anterior and posterior margins darkened, lateral fields brownish with indistinct light pattern. Meso­ and metanotum ( Fig. 49 ) with pale complicated pattern; wing pads with longitudinal dark stripe medially and light margins. Legs yellowish ( Fig.49 ); tibiae with fringe of silky swimming hairs, femora with only short hairs. Abdominal terga ( Fig. 49 ) brownish, with paired pale spots surrounding a brown median stripe, lateral margins entirely pale or with pale spots, posterior edge of terga margined with thick, long fringe of setae. Tenth tergum with large pale heart­shaped spot medially. Cerci ( Figs. 51–53 ) pale yellow, with dorsal silky fringe hairs; in apical part apical whorls with short setae and one ventral seta longer than others, its length not exceeding half the length of its corresponding segment.

Material examined: Mongolia. Turgol R., Hovsgol Lake Basin, 25.VIII 1988, K. Varykhanova, 2 nymphs.

Distribution. Russia: Sayan, Altai Mnts.; Mongolia.

Figures

FIGURES 49 – 53. Isoperla mongolica Zhiltzova: 49. Habitus. 50. Right maxilla, ventral. 51 – 53. Basal and middle and apical sections of right cerci, lateral. Not to scale.