Corethrella (Corethrella) atricornis Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 188-189

Corethrella (Corethrella) atricornis Borkent , new species

DIAGNOSIS: Male adult: unknown. Female adult: only extant species of Corethrella in the New World with the clypeus wider than long ( Fig. 18 AM), palpal segment 3 elongate and slightly swollen subapically ( Fig. 35S), flagellomeres 1–3 each elongate ( Fig. 32D), flagellomere 3, 9–12 each with one sensillum coeloconicum, a distinct midlength wing band, with broad subbasal band extending posterior to CuA (Fig. 72D), thorax dark brown ( Fig. 58B), halter light brown, much paler than scutellum, midfemur dark brown and equal to that of base of hind femur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur), hind tibia with basal and apical pigmentation discrete ( Fig. 58B), and midfemur without scales.

DESCRIPTION: Male adult. Unknown. Female adult. Descriptive statistics: see Tables 6–11. Head: Outline in anterior view laterally elongate ( Fig. 14E). 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 1–11 dark brown (12–13 missing); pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 32D, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18 AM) wide. Mandible with small, pointed teeth. Palpus ( Fig. 35S) pale, with segment 5 light brown; segment 3 elongate, swollen apically. Thorax ( Fig. 58B): Dark brown, pale sclerites around base of wing. Posterior portion of dorsocentral row with group of about 5 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. 72D): Apex of R 2 basal to apex of M 1. Anterior margin with differently, discretely pigmented scales (indicating anterior margin of midlength band), broad subbasal band extending posteriorly to CuA, with midlength band; veins (other than costa and wing margin) with well-developed scales. Halter light brown, lighter than scutellum. Legs ( Fig. 58B): Dark brown with knees of fore-, midlegs pale, hind femur with apical 0.4 pale, hind tibia pale with basal and apical discrete dark brown pigmentation. With only slender setae, lacking scales (except for 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: Medium brown with segments 8-9 dark brown. Cercus dark brown.

Immatures. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella atricornis is known only the type locality in Brazil (Fig. 137) at an altitude of 603 m. It is uncertain how the holotype was collected .

TAXONOMIC DISCUSSION: The holotype was originally on a pin but was placed on a microscope slide for this study.

TYPE: Holotype, female adult on microscope slide, labeled " HOLOTYPE Corethrella atricornis Borkent ”, “Paratipo”, “ Corethrella cardosoi Lane , 41”, “ S. Paulo, Casa Grande, Bar. & Galv. Col. XII-40” ( USNM).

DERIVATION OF SPECIFIC EPITHET: The name atricornis (black, horn) refers to the dark antenna of this species (also present in some other species).