Corethrella (Corethrella) inepta (Annandale)

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 91-92

Corethrella (Corethrella) inepta (Annandale)

Ramcia inepta Annandale 1911:189 . Type locality: Diyatalawa, Ceylon [= Sri Lanka]. Lectotype male adult and associated pupal exuviae, here designated (BMNH). MacDougall 1912:71.

Corethrella inepta: Brunetti 1920:185 . Edwards 1930:529. Barraud 1934:439.

DIAGNOSIS: Male adult: only extant species of Corethrella in the Palaearctic and Oriental Regions with a midlength wing band (Fig. 62H), the midfemur uniformly medium brown and the hind tibia with dark pigmentation restricted to its apical 1/4 ( Fig. 45A). Female adult: unknown.

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view unknown. 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. 21B, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Clypeus squarish, few setae present (probably 3 or less; visibility limited). Palpus dark brown; segment 3 of nearly constant width (other segments not clearly visible). Thorax ( Fig. 45A): Light brown with anterior portion of scutum, anepisternum, katepisternum, posterior portion of mediotergite more darkly pigmented. 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. 62H): 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; veins (other than costa and wing margin) with well-developed scales. Halter pigmentation uncertain. Legs ( Fig. 45A): Medium brown with following light brown or pale: approximately basal 1/5 of midtibia (not discrete), basal 3/4 of hind tibia. 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. 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. 77I): Light brown with subcutaneous dark mottling. Genitalia (Fig. 88B): Gonocoxite uniformly pale, gently tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae 1 slightly thinner than others, with row curving posteromedially with posteriormost seta of row positioned dorsomedially. With one dorsomedial stout seta, tapering from base. Gonostylus (partially extended) nearly straight for basal 3/4, gently curved for apical 1/4, slender, basal half thicker than apical half, tapered apically; one elongate, somewhat slender subbasal seta, situated anteriorly or anteroventrally; condition of apex uncertain, possibly with a blunt peg. Aedeagus slender, elongate, tapering gradually to apex, pointed apically, with lateral margins fused at apex.

Female adult. Unknown.

Pupa. Described by Annandale (1911). Thorax: Scutum, metathorax each with spherical sensory pit (as in Fig. 100A). Respiratory organ (Fig. 101G): Tubular. Abdomen (Fig. 105B): Segments 3–7 not expanded laterally. Paddle only moderately elongate; apicodorsal thick spine articulating; apicoventral seta longer than thick spine.

Larva. Described by Annandale (1911).

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella inepta is known only from the type-locality in Sri Lanka (Fig. 115A) at an altitude of 1499 m. The single male adult was reared from at least the pupal stage. The swamp from which C. inepta was originally collected was reported to be drained ( Annandale 1911; Senior-White 1927:65). Annandale (1911) reported the altitude to be 4,300 feet (= 1291 m) but I have assumed here that modern measurement of the type locality is more accurate.

TAXONOMIC DISCUSSION: The adult is likely somewhat teneral, so that the degree of its thoracic and abdominal pigmentation are uncertain. The form of the aedeagus and apex of the gonostylus were difficult to interpret and appeared to be poorly sclerotized.

Annandale (1911) described C. inepta on the basis of one male adult and at least one pupa and one larva. I have studied one male and a male pupal exuviae on one slide and two whole larvae on a second slide. Both slides are labeled with similar information and handwriting. Annandale’s (1911) drawing of the larval habitus (his Fig. 8) matches one of the two larvae on the slide, with the exception that the drawing shows the antenna as partially extended, while in the specimen at hand they are appressed against the sides of the head capsule. Annandale’s (1911) drawing of the pupa does not match that of the pupal exuviae studied here; his drawing shows a whole pupa, including the developing adult eye and suggests that he may examined further material which I have not seen.

Because Annandale (1911) did not designate a holotype, I here propose making the male adult and associated pupal exuviae the lectotype.

MATERIAL EXAMINED: Lectotype, here designated, adult male with pupal exuviae on microscope slide, labeled “ Corethrella inepta (Annandale) , Lectotype, desig. A. Borkent ”, “ Ceylon, Ramcia inepta Ann. , ♂ imago and pupal skin, IV-1, Type, Diyatalawa”, “Major MacDougall, Mility (sic) Hospital, COLOMRD, Figured, 1911.463” ( BMNH). 2 larvae on 1 slide, paralectotypes labeled as for lectotype but with “(larvae)”, “IV-10" and “Military” ( BMNH).

DERIVATION OF SPECIFIC EPITHET: The name inepta (unsuitable, absurd) probably refers to distinctive features of the adult and larvae of this species noted by Annandale (1911), who placed it in its own genus Ramcia (named as an acronym of the Royal Army Medical Corps).