Corethrella (Corethrella) blanda Dyar, 1928

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 81-84

Corethrella (Corethrella) blanda Dyar

Corethrella blanda Dyar 1928:79 . Type locality: Las Sabanas, [Canal Zone], Panama. Holotype ♂ (USNM?). Lane 1953:81.

Corethrella iridescens Lane 1939b:389 . Type locality: Juquiá , São Paulo, Brazil. Holotype ♀ (DEFS). New synonym.

Corethrella (Lutzomiops) iridescens: Lane 1942:127 .

Lutzomiops iridescens: Lane 1953:97 . Lane and Cerqueira 1958:564.

DIAGNOSIS: Male adult: nearly the only extant species of Corethrella in the New World (not distinguishable from some C. pallid a) with palpus entirely dark brown (as in Fig. 8B), a nearly completely plain wing (with slight non-discrete pigmentation at midlength) (Fig. 62E), wing length of males = 1.10–1.35 mm, scutum light brown and somewhat variably pigmented (but not with lateral vitta dark brown), katepisternum with dorsal margin pale and remainder either completely pigmented or somewhat mottled, halter as dark as scutellum (as in Fig. 43D), midfemur with darker pigmentation at its base and hind tibia with at most slightly darker pigmentation at very base (as in Fig. 43D). Female adult: only extant species of Corethrella in the New World with flagellomeres 1–3 elongate ( Fig. 27G), a nearly completely plain wing (with slight non-discrete pigmentation at midlength) (Fig. 68A) and the hind tibia with at most slightly darker pigmentation at very base ( Fig. 43D).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view later- ally elongate (as in Fig. 8B). Four large setae on frons between ventromedial area of ommatida (as in Fig. 16D). Four large setae on frons between ventromedial area of ommatida (as in Fig. 16D). Four large setae on frons between ventromedial area of ommatida (as in Fig. 16D). Antenna uniformly brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 20H, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus brown; segment 3 of constant width. Thorax (as in Fig. 43D): Light brown, with scutum somewhat mottled, katepisternum with dorsal portion pigmented with remainder mostly uniformly light brown with pale posterior patch to mottled, pale sclerites around base of wing. Posterior portion of dorsocentral row with 2 elongate setae situated somewhat lateral to one another. 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. 62E): Apex of R 2 equal to apex of M 1. Mostly plain, with very light poorly defined midlength band, anterior margin of wing uniformly pigmented; veins (other than costa and wing margin) with well-developed scales. Halter as dark as scutellum. Legs (as in Fig. 43D): Light brown, with fore femur somewhat darker in some, base and apex of midfemur, very base of hind tibia with darker pigmentation; fore-, hind tibia with patch of dark scales. Femora, tibiae and at least some tarsomeres with broad 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 bilobed in dorsoventral view, with claws subapical (as in Fig. 75E). Elongate claw of foreleg shorter than that of midleg, both longer than those of hind leg. Each claw without inner tooth. Anterior claws of each leg without a basal prong. Foreleg claws unequal. Midleg claws unequal. Foreleg third tarsomere longer than fourth tarsomere. Empodia of intermediate thickness. Abdomen (Fig. 77F): Uniformly light brown. Genitalia (Fig. 87C): Gonocoxite uniformly pale, somewhat strongly tapering; anteromedial area with distinctively elongate spicules; with well-defined dorsal row of setae, with 3–4 basal setae of row stout, enlarged and bent subapically, 2 more posterior setae slender, with row restricted to dorsal portion of gonocoxite. With two dorsomedial stout setae, anterior seta more or less of even thickness for most of length, tapering near apex, posterior seta tapering from base, anterior seta more stout, bases joined by sclerotized plate. Gonostylus (in retracted position) straight, basal 0.6 thick, narrowed beyond to rounded apex; one elongate, thick subbasal seta, situated posteroventrally; apical seta slender, elongate, simple. Aedeagus squat, somewhat triangular, tapering gradually to apex, pointed to slightly rounded 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. 16D). Antennal flagellomeres as in Fig. 27G, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 17X) squarish. Mandible with large, triangular teeth. Palpus as in Fig. 33Z. Wing (Fig. 68A). Legs: Apices of fore-, midleg fifth tarsomeres undivided, with claws situated slightly subapically to apically. Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: uniformly light to medium brown.

Pupa. Described by Dyar (1928). Thorax: Scutum, metathorax spherical sensory pits unknown. Respiratory organ (Fig. 101E): Broadly flattened, with spiracles along outer margin. Abdomen (as in Fig. 104D): Segments 3–7 strongly expanded laterally. Paddle uncertain.

Larva. Described by Dyar (1928).

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella blanda is known from Costa Rica, Panama, Colombia, Trinidad and Tobago, French Guiana, and Brazil (Fig. 126) at altitudes ranging from 5– 500 m. Specimens have been collected using light, malaise and frog-call traps (using Hyla gratiosa in Costa Rica and Physalaemus pustulosus in Panama), and rearing. The reared specimens were from Panama and came from small to large ground pools and a roadside ditch. Dyar (1928) mentioned that the type series of C. blanda was reared from larvae collected from a shaded grassy pool in Panama. The serrate mandibles of the female adults and their attraction to frog calls suggest that they feed on frog blood in nature.

Specimens collected with the frog-call trap from Hitoy Cerere Biological Reserve in Costa Rica made up only 1.33% of the 754 Corethrella females collected there on Oct. 11, 2003. Similarly, of 442 Corethrella collected at La Selva Biological Station in Costa Rica, March 2, 2004, only five female adult C. blanda were present (0.9%); female adult C. blanda were also rare in much larger samples from the same place and time but these samples were not counted. 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 males and females were collected together at two locations in Panama. Males cannot be distinguished structurally from most of those of C. pallida but are, on average, smaller and this is discussed further above, under C. pallida .

Dyar (1928) described the male, female, pupa and larva of C. blanda and recorded the “type” male as on a microscope slide and the presence of a further male and female. The type series therefore is composed of a holotype male and the following paratypes: 1 ♂, 1 ♀, at least 1 pupal and 1 larval exuviae. Belkin et al. (1965, Part V) recorded the holotype from the USNM, but it cannot be located now (T. Gaffigan, pers. comm.). I did study two females labeled from the type locality and with the label “Type No. 40517" which is the number Dyar (1928) recorded for this species. I consider both these females to be paratypes and that Dyar misidentified a female as a male. The pupal and larval exuviae also appear to have been lost, although Stone is recorded as having seen the pupa of C. blanda in the USNM ( Lane and Aitken 1956:530).

The holotype of C. iridescens was initially on a pin and was subsequently slide-mounted. It is in good condition. It differed from the other specimens studied here in having somewhat shorter flagellomeres 1–3. However, I found no further differences and therefore consider this intraspecific variation and that C. iridescens is a synonym of C. blanda .

Lane and Cerqueira (1958:564) described the male, pupa and larva of this species (as Lutzomiops iridescens ) but I was unable to reexamine their material and thereby confirm their identification. Their drawing of the male genitalia does not match that of C. blanda here (their drawing of the gonostylus is much more slen- der), indicating that they had another species (not recognized here). Lane and Cerqueira (1958) designated a male as the allotype for C. iridescens and Lane and Aitken (1956) designated an allotype female for C. blanda but these designations are clearly against the rules of the ICZN. Lane and Aitken (1956) recorded this species from Trinidad and Tobago but I have not seen any material of C. blanda from that country.

MATERIAL EXAMINED: Holotype, adult female on microscope slide, labeled “ Corethrella iridescens Ln 39, holotypo, S. Paulo, Juquiá, J. Lane col. 1.148, S. 97, T959, Corethrella blanda Dyar Det. A. Borkent ” ( DEFS). 2 ♀ paratypes of C. blanda, Las Sabanas , Panama, Type No. 40517 ( USNM); 4 ♀, Tárcoles, Costa Rica, 5 m, 11-XI-1993, CD1663 (3, CNCI; 1, INBC); 1 ♂, Bagaces, Palo Verde National Park, Guanacaste, Costa Rica, 250m. 8-XII-1999 - 8-I-2000 ( CNCI); 1 ♀, Manuel Antonio National Park, Costa Rica, 17-XI-1993 ( CNCI); 1 ♂, Peralta,Turrialba, Barbilla National Park , Cartago, Costa Rica, 500 m, 22-V-2001 ( INBC); 2 ♀, nr administration building (9°58.52'N, 83°27.15'W), Barbilla National Park , 500 m, 10-II-2006 ( CNCI); 14 ♀, La Selva Biological Station , Puerto Viejo de la Sarapiqui , Heredia, Costa Rica, 40 m, 1-III-2004 (13 ♀, CNCI; 1 ♀ INMA); 6 ♀, Hitoy Cerere Biological Reserve , nr. administration building (9°40.30'N, 83°01.20'W), 100 m, 11-X-2003 ( CNCI); 1 ♂, 1 ♀, Chiva Chiva , Fort Clayton , Canal Zone , Panama, 30 m, 12-XI-1965 ( USNM); 1 ♂, across canal from Paraíso , Canal Zone , Panama, 50–180 m, 21-XI-1965 ( USNM); 1 ♂, about 5 km NE Nuevo Emperador, Canal Zone , Panama, 90 m, 23-XI-1965 ( USNM); 1 ♂, about 5 km NE Nuevo Emperador, Canal Zone , Panama, 100 m, 23-XI-1965 ( USNM); 1 ♀, 15 km NW Gamboa, Canal Zone , Panama, 30 m, 1-XII-1965 ( USNM); 2 ♀, 9°07.0'N, 79°41.9'W, Gamboa , Canal Zone , Panama, 27 m, 12-VII- 2003 ( XBCP, CNCI); 1 ♂, 1 ♀, Army School Malar , Panama ( USNM); 1 ♀, Canos Negros , 10 km E. Villavicencio, Meta , Colombia, 350 m, 3-VIII-1971, ( USNM); 1 ♀, Finca La Corocora , Villavicencio , Meta, Colombia, 450 m, 15-VII-1971 ( USNM); 2 ♂, Finca Porvenir , Villavicencio , Meta, Colombia, 450 m, 21-VII-1971

( USNM); 1 ♀, Leticia, Colombia, 24-II–1-III-1974 ( CNCI) ; 2 ♀, 24 km SW Cayenne , Guyane, French Guiana, 5 m, 1–2-II-1965 ( USNM) ; 1 ♀, Esperanza Estate, Vega de Oropouche , Trinidad and Tobago, W.I. 12- XII-1960 ( USNM) ; 1 ♀, Guana River Pump Stations, Instituto de Pesquisas e Experimentacao Agropecuarias do Norte, nr Belem, Para, Brazil, 30 m, 29–30-IX-1970 ( USNM) .

DERIVATION OF SPECIFIC EPITHET: The name blanda probably refers to relatively plain legs and wings of this species.