Corethrella (Corethrella) bicolor Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 106-108

Corethrella (Corethrella) bicolor Borkent , new species

DIAGNOSIS: Male adult: only extant species of Corethrella in the New World with the palpus dark brown (as in Fig. 9G), thorax dark brown ( Fig. 47C), a distinct midlength wing band and with or without dark scales more basally but if present then these are along anterior and posterior margin of wing (Fig. 63B), midfemur dark brown and equal to that of base of hind femur, base of hind tibia with small patch of light to dark pigmentation (contrasting with pale apex of hind femur) (as in Fig. 47C), midfemur without scales, abdominal segment 1–8 light brown with sternites 1–2 medium to dark brown, and gonocoxite pale and contrasting with dark brown segment 9 (Fig. 78E). Female adult: only extant species of Corethrella in the New World with flagellomeres 1 and 2 short with flagellomere 1 nearly globular, flagellomere 3 elongate ( Fig. 28I), a distinct midlength wing band and no dark scales more basally (Fig. 69A), thorax dark brown ( Fig. 47C), midfemur dark brown and equal to that of base of hind femur, base of hind tibia with small patch of light to dark pigmentation (contrasting with pale apex of hind femur) ( Fig. 47C), midfemur without scales.

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 9G). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16E). Antenna light brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 21J, sensilla coeloconica distributed as in Table 1; flagellomere 13 with welldeveloped apical bifurcation. Palpus dark brown; segment 3 ovoid, swollen at or near midlength. Thorax (as in Fig. 47C): 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. Ventral portion of posterior anepisternum triangular, uniformly brown, with anterodorsal margin thick. Wing (Fig. 63B): Apex of R 2 basal to apex of M 1. Anterior margin with differently, discretely pigmented scales (indicating anterior margin of midlength band), with midlength band but no dark scales on R 4+5, M, CuA 2; veins (other than costa and wing margin) with well-developed scales. Halter light brown, paler than scutellum. Legs (as in Fig. 47C): Dark brown with knees of fore-, midlegs pale, hind femur with apical 0.4 pale, base of hind tibia with small patch of discrete light to dark pigmentation, apex with discrete dark pigmentation, hind tibia pale at midlength, at least mid-, hind leg tarsomeres 2–4 with banding. With only slen- der 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. Apices of fore-, midleg fifth tarsomeres undivided, with claws slightly subapical to apical (as in Fig. 75F). Claw of foreleg longer than those of mid-, hind leg. Each claw without inner tooth. Anterior claws of each leg without a basal prong. Foreleg claws unequal. Midleg claws equal. Foreleg third tarsomere shorter than fourth tarsomere. Empodia slender. Abdomen (Fig. 78E): Light brown, with sternites 1–2 dark brown, sternites 5–7 medium brown, segment 9 dark brown. Genitalia (Fig. 90A): Gonocoxite pale, strongly tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae 2, 3 slightly thicker than others, with row restricted to dorsal portion of gonocoxite. With one dorsomedial stout seta, more or less of even thickness for most of length, tapering near apex. Gonostylus (partially extended) straight for most of length, curved apically, slender, of more or less equal thickness for entire length, somewhat expanded apically, apex rounded; one elongate, slender subbasal seta, situated anteriorly or anteroventrally; apical seta slender, slightly elongate, simple. Aedeagus slender, elongate, tapering from base, pointed apically, with lateral margins fused at or near apex.

Female adult. Descriptive statistics: see Tables 6–11. As for male, with following differences. Head: Coronal suture short, not extending ventrally between ommatidia (as in Fig. 16E). Antennal flagellomeres as in Fig. 28I, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 17 AL) wide. Mandible with small, pointed teeth. Palpus as in Fig. 34H. Wing (Fig. 69A): similar to male but some with additional darkened scales on M, CuA 2 in midlength band. Halter light to medium brown, lighter than scutellum. Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Light brown with sternites 1–2, segments 8–9 dark brown; in some with segments 5–7 medium brown. Cercus medium brown.

Pupa. Mostly undescribed. Thorax: Scutum, metathorax each with spherical sensory pit (as in Fig. 100A). Respiratory organ (Fig. 102A): Tubular. Abdomen (Fig. 106B): Segments 3–7 somewhat expanded laterally. Paddle only moderately elongate; apicodorsal thick spine articulating; apicoventral seta longer than thick spine.

Larva. Undescribed.

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella bicolor is known from only from the type locality in Brazil (Fig. 122) at an altitude of 20– 30 m. All the specimens were reared from the leaf axils of a terrestrial plant ( Ischnosiphon ) in deeply shaded forest. All were specimens from the Belkin “Mosquitoes of Middle America” project and are listed in Table 12.

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a distinctive pigmentation pattern and were reared together.

TYPES: Holotype, male adult on microscope slide, larval and pupal exuviae on separate slide, labeled " HOLOTYPE Corethrella bicolor Borkent ”, “ Macambo Forest , IPEAN, Belem, Brazil, 20–30 m, 8–29-VII- 1969, T.H.G. Aitken ”, “ Corethrella sp. 43”, “BRA 49-24 Brasil Mosq Mid Amer” ( USNM) . Allotype, female adult on microscope slide, larval and pupal exuviae on separate slide, labeled as for holotype but BRA 49-38

(USNM). Paratypes: 4 ♂, 3 ♀, each with larval and pupal exuviae, from type locality (1 ♂, 1 ♀, CNCI; others to USNM) .

DERIVATION OF SPECIFIC EPITHET: The name bicolor (two colors) refers to the contrast between segment 9 and the gonocoxites of males of this species (also present in some other species).