Nephaspis Casey, 1899: 168. Type species: Nephaspis gorhami Casey, 1899, by subsequent designation of Gordon 1972: 148.

Nephasis: Korschefsky 1931: 168; Blackwelder 1945: 445 (misspelling).

Body elongate oval, moderately convex, with dense pubescence, widest around middle of elytra.

Head with mouthparts directed posteroventrally in repose (Fig. 1a), concealing prosternum; frons wide (Fig. 1a), clypeus extended beyond eye, truncate anteriorly with large, apically rounded flange. Eyes large, finely faceted, inner ocular margin slightly arcuate. Antennae composed of 11 antennomeres (Fig. 1d); 1st antennomere strongly enlarged, curved and distinctly rounded on inner side; 2nd shorter and narrower than the 1st; 3rd obviously smaller than the 2nd; 4th to 6th as wide as 3rd; 7th to 11th forming a fusiform club (Fig. 1d). Labrum exposed, transverse, feebly emarginate anteriorly (Fig. 1a). Mandible with single apical tooth (Fig. 1c). Terminal maxillary palpomere stout, moderately securiform, apical margin strongly obliquely truncate (Fig. 1e). Labial palps with 3 palpomeres, terminal palpomere blunt, subcylindrical (Fig. 1f).

Figure 1.  

Figure 1. Main characters of the genus Nephaspis Casey: (a) head; (b) prothorax, ventral; (c) mandible; (d) antenna; (e) maxilla; (f) labium; (g) hind leg; (h) front leg; (i) tarsi; (j) part of abdominal ventrite 1 and 2. Scale bars: a =0.5 mm, b =0.2 mm, c–j =0.1 mm.

Pronotum convex, hind margin wider than anterior one (Fig. 2b, Fig. 2e). Pronotal hypomeron broad without delimited foveae (Fig. 1b). Prosternum short, straplike, slightly longer than anterior coxa, prosternal process very short, transversely oval (Fig. 1b); prosternal carinae narrowly separated, distinctly convergent anteriorly. Scutellum triangular (Fig. 2a). Elytra slightly wider than pronotum at base, surface finely punctate. Elytral epipleuron narrow and nearly horizontal, inner carina apically incomplete, reaching up to 1st abdominal ventrite. Mesoventrite short, tumid medially, anterior margin truncate, intercoxal area with hind margin deeply emarginate. Metaventrite strongly tumid, anterior margin distinctly ridged, median area strongly prominent forward. Abdomen with six ventrites (Fig. 2g). Abdominal postcoxal lines incomplete (Fig. 1j, Fig. 2g). Front leg slender (Fig. 1h), femora of hind leg distinctly enlarged (Fig. 1g); tibiae without apical spur; tarsi with 4 tarsomeres, claws simple without basal teeth (Fig. 1i).

Figure 2.  

Figure 2. Nephaspis indus Gordon, 1996: (a–c) male; (d–f) female; (a, d) dorsal view; (b, e) frontal view; (c, f) lateral view; (g) abdomen; (h) penis; (i) apex of penis; (j) tegmen, ventral view; (k) tegmen, lateral view. Scale bars: a–f = 0.5 mm, g–h = 0.2 mm, i–k = 0.1 mm.

Nephaspis Casey is similar to the Old World genus Clitostethus Weise, 1885 in general appearance and shares the following characters with the latter: body small, length less than 2 mm; antennae composed of 11 antennomeres (Fig. 1d); prosternum straplike, prosternal process short, transversely oval (Fig. 1b); abdominal postcoxal line incomplete (Fig. 1j, Fig. 2g); abdomen with six ventrites (Fig. 2g). Nephaspis is separated from Clitostethus mainly by the tarsi with 4 tarsomeres (Fig. 1i) and the stout basal antennomere (Fig. 1d). However, Clitostethus has the tarsi with 3 tarsomeres and the slender basal antennomere.

This genus is apparently endemic to Neotropical region with a natural geographic range extending from southern United States (Florida, Louisiana and Texas) and Mexico to Argentina (Gordon 1996). In addition, several species of this genus are specialist predators of the spiralling whitefly, Aleurodicus dispersus. As important biological control agents against the spiralling whitefly, these members of Nephaspis have been introduced into different parts of the world, such as Hawaii, Guam, Fiji, Taiwan and Thailand (Waterhouse and Norris 1989, Chien et al. 2002, Napompeth 2004).

Nephaspis indus Gordon, 1996: 43;Yu 2011: 88.

Nephaspis amnicola: Yoshida and Mau 1985 (nec. Wingo 1952​)

TL: 1.23–1.32 mm, TW: 0.87–0.92mm, TH: 0.67–0.69mm, TL/TW: 1.41–1.43, PL/PW: 0.52–0.53, EL/EW: 1.05–1.07, HW/PW: 0.61–0.62, PW/EW: 0.84–0.85.

Body rounded oval, moderately convex, dorsum covered with white pubescence (Fig. 2a–f). Head, antennae and mouthparts yellow in male (Fig. 2a–c). Pronotum yellow with dark brown at central base. Scutellum black. Elytra black with apical 1/15 yellow. Prothoracic hypomeron and prosternum yellow. Mesoventrite and metaventrite reddish brown to black. Elytral epipleuron black. Legs yellow.

Head with fine frontal punctures, as large as eye facets, 0.5 diameter apart. Eyes densely faceted, interocular distance 0.44 times head width. Pronotal punctures smaller than those on frons, 1.0–1.5 diameters apart. Surface of elytra with punctures larger than those on pronotum, separated by 1.0–2.0 diameters. Prosternal process very short, transversely oval (Fig. 1b). Abdominal postcoxal lines strongly recurved and distinctly incomplete laterally (Fig. 2g), nearly reaching posterior margin of abdominal ventrite 1, area enclosed by lines coarsely punctate, broadly smooth along line. Abdominal ventrite 5 with apex truncate in both sexes.

Male genitalia. Penis long, strongly curved at basal 1/2 length (Fig. 2h); penis capsule with long inner arm and short outer arm; apex of penis with membranous appendage (Fig. 2i). Tegmen stout (Fig. 2j–k) with penis guide widest at base, tapering gradually to pointed apex in ventral view (Fig. 2j) and its base with prominent dorsal keel in lateral view (Fig. 2k). Parameres tapering toward apex, as long as 2/3 length of penis guide, covered with several long setae at apices (Fig. 2k).

Female externally similar to male but with black pronotum (Fig. 2d) except anterolateral angles yellow (Fig. 2e–f); head yellow with vertex dark brown (Fig. 2e).

This species is similar to Nephaspis bicolor Gordon, 1982 in general appearance, but can be distinguished from the latter by details of male genitalia, particularly the stout penis guide with a dorsal keel at basal 1/3 length in lateral view (Fig. 2k) and the black pronotum with yellow anterolateral angles in female (Fig. 2e). In N. bicolor, the penis guide with a high dorsal keel at basal half in lateral view and the yellow pronotum with median 1/3 dark brown in female (Gordon 1996).

Taiwan, Hawaii, Trinidad, Honduras.

There was some confusion about the taxonomy and nomenclature of N. indus. This species was introduced from Honduras, Trinidad and the West Indies into Hawaii as N. amnicola in 1979–1980 where it became effective in biological control of the spiralling whitefly (Kumashiro et al. 1983). A few years later, Gordon (1996) described a new species, N. indus, based on the specimens from Hawaii. Actually, this is a Trinidadian species, although the type series were all from Hawaii. He also pointed out that the male genitalia figured in Gordon (1982) for N. bicolor are those of N. indus, because a male of the latter species was mixed in with the type series of N. bicolor and that was the specimen selected for illustration (Gordon 1996).