20. Labiobaetis operosus (Mueller-Liebenau, 1984) Figures 35, 53b

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of ca. ten feathered setae; B) labial palp segment II with thumb-like distomedial protuberance, segment III slightly pentagonal, apically slightly truncate; C) hypopharynx with medial tuft of stout setae well developed; D) fore femur rather slender, length 3.8 × maximum width, dorsal margin with a row of ca. ten spine-like setae; E) paraproct distally not expanded, with ca. 16 stout marginal spines.

Examined material.

Holotype. 1 larva (on slide, no. 34), W. Malaysia, Gombak River, 4½ miles N of Kuala Lumpur, nr. Bentong road, 18.IX.1969, Bishop leg.