Diaphorocoris Montandon, 1897

Sites, Robert W. & Zettel, Herbert, 2011, Waterfall-inhabiting Naucoridae (Hemiptera: Heteroptera) of southern India and Sri Lanka: Pogonocaudina Sites and Zettel, n. gen., and a review of Diaphorocoris with descriptions of two new species, Zootaxa 2760, pp. 1-17 : 9

Genus Diaphorocoris Montandon, 1897

Supplemental redescription. Head angled ventrad ca. 30o with respect to pronotum; compound eyes divergent, mesal margins concave, lateral margins convex in posterior half, concave in anterior half, convergent anteriorly; lateral hyperoche widening anteriorly; apex of head deflexed, oriented posteroventrally; anteroventrally impunctate, with line of elongate setae between eye and base of labrum; rostrum short, segment three (first visible anteriorly) partially concealed behind well developed labrum, segment four narrower, reaching to near middle of prothoracic coxae; maxillary plates small, with brush of long hairs distally; antennal segments pale, one and two short and inconspicuous, three widest in distal 1–2; antennae set behind strong proepisternal flange and brushes of long setae ventrally on head and proepimeron. Pronotum with lateral margins smooth, convex; posterolateral corners rounded. Hemelytra with well developed embolium and clavus, short clavate hairs in linear series, costal fracture beyond embolium. Embolium with marginal row of spines, yellowish anterior band gradually narrowing posteriorly and becoming obsolete before costal fracture, with notch-like mesal incursion of white or light yellow into dark brown at level of scutellar apex. Prosternal midline with wedge-shaped carina between coxae, lateral surface of carina yellow. Forelegs with femur broad; tibia narrow; tarsus two-segmented in male, one-segmented in female; paired, articulated claws in both sexes. Middle and hind coxae with ventromesal series of stout hairs. Middle and hind legs with femora flattened, slightly curved dorsad, with row of spines along anteroventral margin and stronger spines along posteroventral margin; tibiae with numerous stout spines. Middle tibia gradually widening apically; male with dense pad of hairs beginning at proximal 1/4 of ventral surface and widening distally, pad reduced on female; scattered weak posterior spines, multiple rows of heavy anterior spines, weak fringe of posterodorsal swimming hairs continuing onto tarsi. Hind leg with tibia elongate, scattered posterior spines, multiple rows of anterior spines, fringe of posterodorsal swimming hairs on tibia continuing onto tarsi; tarsomere one produced beneath base of tarsomere two. Mid- and hind pretarsi with claws elongate, evenly curved, symmetrical, each with small basal tooth. Hindwing with well-developed veins C, R, M, Cu, m-Cu, pCu, pCu-A, 1A, 2A; cells R, M; anal fold.

Diagnosis. These naucorids are elongate and flattened, with eyes elevated above the level of the pronotum, and with a wide, triangular lateral hyperoche of the head. They have most of the features common to members of Laccocorinae , including the front of the head being folded posteroventrally; the labrum is well developed, transverse, and rounded apically; and the dense midventral abdominal band of hairs, which is present on only three other genera. The middle tibia has a sexually dimorphic pad of hairs that widens distally, which is well developed on the male and reduced on the female. The front tarsi are two-segmented in males, unlike Namtokocoris and Pogonocaudina , which have single segmented front tarsi in males. The front pretarsal claws are paired in both sexes, unlike Namtokocoris , which has a single, unmovable claw. The scutellum is very large, elevated, and with lateral tumescences. The hemelytra have linear series of short, stout hairs, a feature which has been overlooked by each previous taxonomic treatment of the genus, including by Distant (1906). This attribute is in common with Namtokocoris .

Discussion. Montandon erected this genus to contain his new species D. notatus in 1897. However, later in the same year, after examining specimens from Sri Lanka given to him by Kirkaldy, he realized that this species had already been described by Kirby (1891) under the genus Naucoris as N. punctatissima ( Montandon 1897b) and, thus, synonymized D. notatus as D. punctatissima . When Kirby described his species, he recognized the uncertainty of this generic placement and commented that this species was narrower than other species of Naucoris and even placed a question mark after the genus in the new species heading.

Little was known about the biology or ecology of this genus. In the original description of the type species, Kirby (1891) indicated that the type species was found on "wet rocks by running water." In a treatment of the fauna of Malesia, this genus was listed as occurring in a quiet pool with silt in a disturbed forest in northern Thailand ( Chen et al. 2005); however, this actually was in reference to Namtokocoris (Nieser, pers. comm.), which was described two years later (Sites & Vitheepradit 2007).