DIAGNOSIS: Male adult: unknown. Female adult: only extant species of Corethrella in Australia with pale or very light brown body (Fig. 37B), rounded head (from an anterior view) (Fig. 6B), and with legs pale but with each tibia with apical light brown pigmentation (Fig. 37B).

DESCRIPTION: Male adult. Unknown.

Female adult. Descriptive statistics: see Tables 6–11. Head: Outline in anterior view nearly circular (Fig. 6B). Coronal suture elongate, extending ventrally past ommatida (Fig. 16B). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16B). Antenna pale; pedicel without distinctive, more elongate, stout, dorsal or dorsolateral setae; flagellomeres as in Fig. 25H, sensilla coeloconica distributed as in Table 1. Mandible with very small, pointed teeth. Clypeus (Fig. 17B) squarish or somewhat wider than long. Palpus (Fig. 33B) pale; segment 3 swollen apically. Thorax (Fig. 37B): pale or very light brown with following slightly darker: patch in middle of scutum, medial area of mediotergite, anterior and posterior anepisternum, ventral portion of katepisternum, dorsal portion of anepimeron. Posterior portion of dorsocentral row with 2 elongate setae situated somewhat lateral to one another. Prescutal suture elongate, thick, uninterrupted, extending to near dorsocentral row of setae. Anterior anepisternum divided diagonally by sinuous suture, dorsal portion larger than ventral portion. Ventral portion of posterior anepisternum triangular, uniformly brown, with anterodorsal margin not thick. Wing (Fig. 66B): Apex of R 2 equal to apex of M 1. Dark pigmentation on veins and immediately adjacent area in area from forking of R 1 +Rs posteriorly to fork of CuA, very apices of R 2, R 3, R 4+5, M 1; veins (other than wing margin) with slender scales. Halter paler than scutellum. Legs (Fig. 37B): Uniformly pale except for light brown band at apex of each tibia. With only slender setae, lacking scales (except for some in patch of whip-like setae on posterior portion of hind tibia). Midleg without thick, subapical setae on each of tarsomeres 1–3. Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Empodia slender. Abdomen: Very light brown but at least tergites 2–6 with light brown anterior band. Cercus very light brown.

Immatures. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella alba is known only from the type locality in Queensland, Australia (Fig. 115B) and was collected near Mission Beach in rainforest habitat at an altitude of 40 m (S. Peck, pers. comm.). The very small mandibular teeth suggests that this species may be autogenous.

TAXONOMIC DISCUSSION: The three paratypes, all on microscope slides, were left too long in KOH during preparation and are unnaturally pale (no pigmentation). The holotype, not so cleared, provided the means of describing the pigmentation patterns.

TYPES: Holotype, female adult on microscope slide, labeled " HOLOTYPE Corethrella alba Borkent, Aust. Qsld, 10 km SE El Arish, Laceys Ck. 23-VI–5-VIII-1982, S.&J. Peck, 40 m, CD482" (ANIC). Paratypes: 3 ♀, labeled as for holotype (CNCI).

DERIVATION OF SPECIFIC EPITHET: The name alba (white) reflects the light pigmentation of this species (also shared with some other Australian species).