Corethrella (Corethrella) melanica Lane and Aitken

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 147-149

Corethrella (Corethrella) melanica Lane and Aitken

Corethrella melanica Lane and Aitken 1956:535 . Type locality: Arima Valley , St. Patrick Estate, Trinidad and Tobago. Holotype ♀ (DEFS).

DIAGNOSIS: Male adult: only extant species of Corethrella in the New World with a primarily pale palpus (apical half of segment light brown) (as in Fig. 12D), a distinct midlength wing band and with more basal dark scales on M and area just distal to arculus (Fig. 64E), with a dark brown thorax (as in Fig. 53C), dark brown midfemur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur) (as in Fig. 53c), all femora with broad scales (as in Fig. 74D), with dorsomedial seta from base/ gonocoxite length = 0.17–0.25 (Fig. 94B). Female adult: only extant species of Corethrella in the New World with a distinct midlength wing band and with extensive basal dark scales (with only small pale patches centered on r-m, along M and A) (Fig. 70K), with a dark brown thorax ( Fig. 53C), dark brown midfemur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur) ( Fig. 53C), all femora with broad scales (as in Fig. 74D).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 12D). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16B). Antenna pale to light brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 23E, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus mostly pale, with apical half of segment 5 light brown; segment 3 of nearly constant width or somewhat swollen subapically. Thorax (as in Fig. 53C): Dark brown, pale sclerites around base of wing. Posterior portion of dorsocentral row with group of about 9 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. 64E): 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, with darker more basal scales restricted to vein M and basal band, some with subbasal band (including those on vein M); veins (other than costa and wing margin) with welldeveloped scales. Halter medium brown, lighter than scutellum. Legs (as in Fig. 53C): Dark brown with knees of fore-, midlegs pale, basal 2/3 of hind femur dark, base and apex of hind tibia with non-discrete dark pigmentation, pale at midlength, at least mid-, hind leg tarsomeres 2–4 with banding. Femora, tibiae with broad scales (also some in patch of whip-like setae on posterior portion of hind tibia). Midleg with thick, sub- apical 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. 79J): Dark brown. Genitalia (Fig. 94B): Gonocoxite dark basally, lightening apically, strongly tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae 1, 2 thicker than others, in some, just seta 2 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) mostly straight, curved near apex, slender, of more or less equal thickness for entire length, expanded apically, rounded to somewhat pointed apically; one elongate, slender subbasal seta, situated anteriorly or anteroventrally; apical seta slender, short, simple. Aedeagus slender, elongate, tapering gradually to apex, pointed apically, with lateral margins fused at apex.

Female adult. Descriptive statistics: see Tables 6–11. As for male, with following differences. Head: Coronal suture elongate, extending ventrally past ommatida (as in Fig. 16B). Antenna medium to dark brown; with flagellomeres as in Fig. 30I, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18T) squarish or somewhat wider than long. Mandible with small, pointed teeth. Palpus as in Fig. 34 AF. Wing (Fig. 70K):as for male but with basal half of wing nearly entirely with dark scales (equal to those of midlength scale), some darkening of scales on apical portion of wing. Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Dark brown. Cercus dark brown.

Pupa. Described by Lane and Aitken (1956). Thorax: Scutum, metathorax each with spherical sensory pit (as in Fig. 100A). Respiratory organ (Fig. 102K): Tubular. Abdomen (Fig. 108D): Segments 3–7 somewhat expanded laterally. Paddle only moderately elongate; apicodorsal thick spine articulating; apicoventral seta longer than thick spine.

Larva. Described by Lane and Aitken (1956).

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella melanica is known from Costa Rica, Panama, Peru, Venezuela, Trinidad and Tobago, and French Guiana (Fig. 131) at altitudes ranging from 10– 740 m. Lane and Cerqueira (1958) recorded the species from Manoas, Brazil but I was unable to reexamine their specimen. Nearly all adult specimens have been reared, most from internodes or holes in bamboo but with a few from treeholes. At La Selva Biological Station, Costa Rica, March 2, 2004, female adult C. melanica were uncommon in the frog-call traps (using Hyla gratiosa ), with only one specimen present in four samples, totaling 422 specimens; a few other specimens were present in larger, uncounted, samples taken at the same place and date. I did not sample this species with the frog-call trap in any other spot in Costa Rica. The serrate mandibles of the female adults and their attraction to Hyla gratiosa calls suggest that they feed on frog blood in nature. The specimens from the Belkin “Mosquitoes of Middle America” project are identified in Table 12.

TAXONOMIC DISCUSSION: Males and females were associated through being reared together the same locality. Lane and Aitken (1956) pointed out that the sexual dimorphism in wing pigmentation in C. melanica is unique in the genus but it is now also known in C. calathicola . Within in all other species of Corethrella the wing pigmentation of the male and female is very similar, with the female often having only slightly darker or slightly more extensive pigmentation.

Most of the type series, including the holotype, were on pins and are now on microscope slides. Two female paratypes, one in poor condition, remain on pins (USNM).

Lane and Aitken (1956) recorded a male allotype and 7 male and 15 female paratypes of C. melanica . I have examined 6 male and 10 female paratypes, all from either DEFS or USNM. The allotype appears to be missing, as well as the remaining paratypes. Lane and Aitken (1956) noted that they planned to send 1 male and 3 female paratypes to the BMNH but only the male is present there. In addition, these authors stated that they planned on depositing 3 male and 6 female paratypes in the USNM but in fact there are 3 males and 8 females in that collection. Finally, Lane and Aitken (1956) described the larval and exuviae from which they reared the adults and these must be considered as paratypes. Two slides, each with a larval and pupal exuviae, are in DEFS, and I have newly labeled these as paratypes.

The holotype of C. melanica was not identified with a label bearing its name (although it did have a label saying “Holotipo”. Its position in the collection with paratypes of C. melanica , the presence of labels indicating the locality and date reported by Lane and Aitken (1956), and its structural features indicate that it is certainly the holotype of C. melanica . A label has been added to identify the specimen as such. Similarly 2 larval and 2 pupal exuviae (DEFS) which were listed by Lane and Aitken (1956) are almost certainly paratypes and I have added a label to indicate this.

There is considerable variation in the relative lengths of the basal flagellomeres, perhaps indicating that more than one species is present under this name.

MATERIAL EXAMINED: Holotype, adult female on microscope slide, labeled “Holotipo”, “St. Pats, Arima, Trin. ex bamboo. 6-6/II/54-1WGD”, “S639 T 6387", “ Holotype Corethrella melanica Lane and Aitken ” ( DEFS). Paratypes: 1 ♂, 1 ♀ labeled as for holotype but 4–6-III-1954 (♂, BMNH; ♀, USNM) ; 2 ♀ labeled as for holotype but 5–23-II-1954 ( DEFS, USNM) ; 1 ♂, 2 ♀ labeled as for holotype but 2-II-1954 ( USNM) ; 4 ♂, 3 ♀, 2 pupal exuviae, 2 larval exuviae, Tabaquite, Trinidad and Tobago, 24-II-1955 (1 ♂, 1 ♀, immatures, DEFS; 3 ♂, 2 ♀, USNM) . Other material: 1 ♀ with larval and pupal exuviae, Estación Quebrada Bonito , Carara National Park, Puntarenas, Costa Rica, 10 m, 3-XII-2002 ( INBC) ; 1 ♂, 2 ♂ each with pupal exuviae, 5 ♀, 3 ♀ with larval and pupal exuviae, 1 ♀ pupal exuviae, El Naranjal , Silvestre Golfito R.N. Golfito, Costa Rica, 80 m, 22-VII-2001 (1 ♂, 1 ♀ each with pupal exuviae, CNCI; others to INBC) ; 1 ♀ with larval and pupal exuviae, 1 ♀ with pupal exuviae, 5 km W. Rincón , Aguabuena , Sierpe, Centro Juvenil Tropical, Costa Rica, 80 m, 11- VIII-2001 ( INBC) ; 7 ♀, La Selva Biological Station , Puerto Viejo de la Sarapiqui, Heredia, Costa Rica, 40 m, 1-III-2004 ( CNCI) ; 1 ♀ with larval and pupal exuviae, Madden Forset Preserve , Summit, Canal Zone, Panama, less than 200 m, 29-XI-1965 ( USNM) ; 1 ♂ with pupal exuviae, 1 ♀ with larval and pupal exuviae, 52 km S. airport, Iquitos , Peru, 10-IX-2002 ( CNCI) ; 1 ♂ with pupal exuviae, from previous locality but 1-II-2003 ( CNCI) ; 1 ♀ with larval and pupal exuviae, Guamitas , Maracay, Aragua, Venezuela, 740 m, 15-VII-1969 ( USNM) ; 1 ♀ with larval and pupal exuviae, 5 km SE Cayenne, Guyane , French Guiana, 20 m, 31-I-1965 ( USNM) .

DERIVATION OF SPECIFIC EPITHET: The name melanica (black) probably refers to characteristic dark wing of the female of this species.