Corethrella (Corethrella) whartoni, Vargas, 1952

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 159-160

Corethrella (Corethrella) whartoni Vargas

Corethrella whartoni Vargas 1952:57 . Type locality: Comalcalco , Tabasco, Mexico. Holotype ♂ (IDRE).

DIAGNOSIS: Male and female adults: only extant species of Corethrella in the New World with the wing without dark scales just distal to the arculus, with dark scales in a subapical band (with no dark scales on these veins extending to the apex of the wing) (Figs. 64J, 71B), and with the hind femur either uniformly dark brown or dark brown and its apex even more darkly pigmented ( Fig. 54D).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 12I). Four large setae on frons between ventromedial area of ommatida (as in Fig. 16G). Antenna medium brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 23J, sensilla coeloconica (as in Fig. 15J) distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus pale or light brown; segment 3 of nearly constant width or slight swollen apically. Thorax (as in Fig. 54D): Dark brown, pale sclerites around base of wing. Posterior portion of dorsocentral row with group of about 4 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. 64J): Apex of R 2 basal to apex of M 1. Anterior margin with differently, discretely pigmented scales (indicating anterior margins of wing bands, with subbasal, midlength, subapical band; veins (other than costa and wing margin) with well-developed scales. Halter as dark as scutellum. Legs (as in Fig. 54D): Femora, tibiae, medium to dark brown with midlength of hind tibia lighter, in some midlength of hind femur, at least mid-, hind leg tarsomeres 2–4 with banding. Midfemur 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. 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. 80C): Medium brown. Genitalia (Fig. 95C): Gonocoxite medium brown, strongly tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae 1–3 thicker than 4, 5; with row restricted to dorsal portion of gonocoxite. With one dorsomedial stout seta, tapering from base. Gonostylus (partially extended) nearly straight, slender, of more or less equal thickness for entire length but somewhat thicker apically, rounded apically; one elongate, slender subbasal seta, situated anteriorly or anteroventrally; apical seta slender, elongate, simple. Aedeagus slender, elongate, tapering gradually to near apex, with slender apex, pointed apically, with lateral margins fused subapically or near apex.

Female adult. Descriptive statistics: see Tables 6–11. As for male, with following differences. Head: Coronal suture short, extending ventrally about midway along area between ommatidia (as in Fig. 16F). Antennal flagellomeres as in Fig. 31A, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18Y) wide. Mandible with small, pointed teeth. Palpus as in Fig. 35E. Wing (Fig. 71B). Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Medium brown. Cercus medium brown.

Pupa. Mostly undescribed. Thorax: Scutum, metathorax without spherical sensory pits. Respiratory organ (Fig. 103C): Tubular, with apical portion somewhat convoluted. Abdomen (Fig. 109D): Segments 3– 7 not expanded laterally. Paddle long, slender; apicodorsal thick spine articulating; apicoventral seta slender, much shorter than thick spine.

Larva. Undescribed.

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella whartoni is known from Mexico, Costa Rica and Panama (Fig. 138) at altitudes ranging from 8–25 m except for the male and female from Coto Brues, Costa Rica, collected at 1400–1500 m. The type specimens were collected with a light trap. Male and females from 5 km NE Tárcoles, Costa Rica were collected with a light trap while a frog-call trap ( Hyla gratiosa ) was running nearby, without the calls attracting any females of this species. The male and female from Coto Brues, Costa Rica were collected by sweeping. The specimens from 1 km S Aranjuez, Costa Rica and Panama were reared from a swamp margin and lake margin respectively. The specimens from the Belkin “Mosquitoes of Middle America” project are identified in Table 12.

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a similar pigmentation pattern and were collected together in Mexico (types) and Costa Rica. The holotype, mounted on a microscope slide, is uncleared and the genitalia is partially shriveled and is missing one gonostylus and the apical half of the other. The allotype female, reported to be mounted on a pin by Vargas (1952), appears to be missing.

MATERIAL EXAMINED: Holotype, adult male on microscope slide, labeled “ Culicidae Corethrella whartoni Vargas ♂ Holoaedotipo, #6249, Col. M. Macias, Comalcalco, Tabasco, Septiembre, 1946” ( IDRE). Paratype, 1 ♀, labeled as for holotype but with #6250 ( IDRE) . 3 ♂, 8 ♀, 5 km NE Tárcoles , Costa Rica, 20 m, 2-IX-1993 ( CNCI) ; 1 ♂, as previous locality but 17-VIII-1993 ( CNCI) ; 1 ♂, 1 ♀, Mellizas Sabalito , Coto Brus, Puntarenas, Costa Rica, 1400–1500 m, 28-XII-1995 ( INBC) ; 1 ♂, with larval and pupal exuviae, La Laguna de Aranjuez , 1 km S Aranjuez, Pitahay, Puntarenas, Costa Rica, 8 m, 15-VIII-1971 ( USNM) ; 1 ♂, with larval and pupal exuviae, Rio Chagres , 1 km S Juan Mina, Chilibre, Canal Zone, Panama, 25 m, 4-VIII-1972 ( USNM) .

DERIVATION OF SPECIFIC EPITHET: The name whartoni was given in honor of G.W. Wharton by Vargas (1952).