Corethrella (Corethrella) hirta Borkent, new species DIAGNOSIS: Male adult: unknown. Female adult: only extant species of Corethrella in the New World with a distinct midlength wing band and with extensive dark scales basal to the midlength band but without any of these on the anal vein (Fig. 70G), with a dark brown thorax (Fig. 52C), dark brown midfemur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur), hind femur with basal 0.6 darkly pigmented (Fig. 52C), and all femora with slender scales. DESCRIPTION: Male adult. Unknown. Female adult. Descriptive statistics: see Tables 6–11. Head: Outline in anterior view laterally elongate (Fig. 11I). Coronal suture short, extending ventrally about midway along area between ommatidia (as in Fig. 16F). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16F). Antennal flagellomeres 1–6 light brown, 7–13 somewhat darker; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 30E, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Clypeus (Fig. 18P) wide. Mandible with small, pointed teeth. Palpus (Fig. 34 AB) pale; segment 3 swollen apically. Thorax (as in Fig. 52C): Dark brown, pale sclerites around base of wing. Posterior portion of dorsocentral row with group of about 8 elongate setae. Prescutal suture short, not extending more than half way to dorsocentral row of setae. Anterior anepisternum divided diagonally by sinuous suture, dorsal portion about equal to ventral portion. Ventral portion of posterior anepisternum triangular, uniformly brown, with anterodorsal margin thick. Wing (Fig. 70G): Apex of R 2 basal to apex of M 1. Anterior margin with differently, discretely pigmented scales (indicating anterior margin of midlength band), with basal/subbasal band extending from C to CuA (no dark scales on A), with midlength band; veins (other than costa and wing margin) with well-developed scales. Halter as dark as scutellum. Legs (as in Fig. 52C): Dark brown with knees of fore-, midlegs pale, basal 0.6 of hind femur dark, hind tibia medium brown with non-discrete dark apical pigmentation. Femora, tibiae with slender scales (also some in patch of whip-like setae on posterior portion of hind tibia). Midleg with thick, subapical setae on each of at least tarsomeres 1–3. Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Empodia slender. Abdomen: Dark brown, with segments 8–9 darker. Cercus dark brown. Immatures. Unknown. DISTRIBUTION AND BIONOMICS: Corethrella hirta is known only from the type locality in Costa Rica (Fig. 119A) at an altitude of 40 m. Adults were collected with a frog-call trap, using the call of Hyla gratiosa, placed at the edge of the “frog ponds” just south of the River Station. The species was not common in the otherwise abundant samples of other species of Corethrella collected at this site on March 1–2, 2004. The serrate mandibles of the female adults and their attraction to Hyla gratiosa calls suggest that they feed on frog blood in nature. Female C. hirta are unique in the family, however, in having the bifid apex of the labrum splayed anterolaterally. These mouthpart modifications suggest that females feed in a distinctive manner or on a distinctive host. TYPES: Holotype, female adult on microscope slide labeled " HOLOTYPE Corethrella hirta Borkent ", “ La Selva Biological Station, Costa Rica, 2-III-2004, A. Borkent, CD5416" (CNCI). Paratypes: 2 ♀, from type locality (CNCI, INBC). DERIVATION OF SPECIFIC EPITHET: The name hirta (hairy) refers to the slender scales on the femora of adults of this species.

Published as part of Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), pp. 1-456 in Zootaxa 1804 on pages 136-137