Protosticta albifrons Kompier, 2016, spec. nov.

2. Protosticta albifrons spec. nov.

(Figs. 6–9)

Type specimens. Holotype Ƌ: Xuan Son National Park, Phu Tho Province, northern Vietnam (21.139 N, 104.938 E), 01-VIII-2016, T. Kompier leg. Allotype ♀: Same date, location and collector. Paratypes: 1Ƌ same location and collector, 31-VII-2016, 2Ƌ same location and collector, 01-VIII-2016. All in RMNH.

Etymology. The specific name albifrons refers to the white bar on the frons of the species. It is a noun in apposition.

Description of male holotype. Head. Anteclypeus and labrum ivory white with inferior margin of labrum black. Genae ivory white adjacent to labrum, laterally black. Antennae brown, first and second segments pale yellow; postclypeus shiny black, centrally and laterally with pale spot along border with antefrons. Frons matte black, centrally with horizontal whitish bar, vertex and occiput entirely black. Prothorax (Fig. 6). Pale yellow, anterior lobe with two oblong dark brown diffuse spots, lateral lobes with diffuse dark brown central spot and posterior lobe largely mottled with brownish, paler along the edges and along center line. Synthorax (Fig. 6). Mesepisternum black with green shine, anteriorly with small diffuse pale area and dorsal carina pale yellow, mesepimeron blackish brown, but posterior dorsal corner pale yellow. Mesinfraepisternum almost completely black, but pale yellow adjacent to coxae. Metepisternum and metepimeron pale yellow, separated by distinct black stripe over metapleural suture continuing over metinfraepisternum. Metepisternum with posterior brownish spot. Legs pale yellow with black stripe over flexor surface; spines and claws pale brown. Wings. Hyaline, 15 postnodal crossveins in forewing, 14 in hindwing. Pterostigma dark brown, covering one cell. Abdomen. Colored as follows: S1–2 dark brown dorsally and pale yellow ventrally, but S2 with pale dorsal central line; S3–7 dark brown with pale yellow anterior apical ring, pale yellow posterior subapical ring and posterior blackish-brown apical ring; S8 blackish brown with whitish ventral mark anteriorly; S9 almost entirely white, edged black along posteroventral corner; S10 blackish brown. Anal appendages (Fig. 7) black; cerci smoothly curved from broad base narrowing somewhat till just before halfway, then strongly curved downward, with broad and rounded dorsal tooth in lateral view, the posterior half of cerci complicated, broad in lateral view, flattened with ridges and incised apically to form three lobes that are partly folded over each other. Paraprocts with elongated tip, tapering, the apical half reminiscent of the hull of a kayak in lateral view, separated from proximal half by narrower neck, the kayak-shaped part at its base with a raised cup-like structure.

Measurements (mm). Hindwing 19; abdomen including appendages 42.

Variation in paratypes. One male with greenish-black dorsal carina. Extent of pale area along border with antefrons on postclypeus varies from almost nothing to almost one third of postclypeus surface. Prothorax always with diffuse mottling on posterior lobe, but extent of brown on anterior and lateral lobes sometimes very limited. Abdomen including appendages 40–43mm, hindwing 18–19mm. Postnodals 13 in forewing and 12 in hindwing in one male.

Description of female allotype (Fig. 9). Head. Labrum bluish white with inferior margin of labrum broadly edged black. Genae black with some white adjacent to labrum. Anteclypeus ivory white. First and second segments of antennae pale yellow, second tipped brown, remainder brown; postclypeus, frons, vertex and occiput entirely black, apart from paler brown horizontal bar over center of frons. Prothorax. Pale yellow, anterior lobe with two oblong dark brown diffuse spots, lateral lobes with diffuse dark brown central spot and posterior lobe with two brown spots. Synthorax. Mesepisternum black with green shine, anteriorly with small diffuse pale area and dorsal carina pale yellow, mesepimeron blackish brown, but dorso-posterior corner pale yellow. Mesinfraepisternum almost completely black, but pale yellow adjacent to coxae. Metepisternum and metepimeron pale yellow, separated by distinct black stripe over metapleural suture continuing over metinfraepisternum. Legs. Pale yellow with black stripe over flexor surface; spines and claws brown. Wings. Hyaline, 14 postnodal crossveins in forewing, 14 in hindwing. Pterostigma dark brown, covering one cell. Abdomen. Colored as follows: S1–2 dark brown dorsally and pale yellow ventrally; S3–7 dark brown with pale yellow anterior apical ring, pale yellow posterior subapical ring (absent on S6–7) and posterior blackish brown apical ring; S8 blackish brown, anterior half of venter pale yellow; S9 completely white apart from black line along anterior margin and along ventral margin, S10 and ovipositor blackish brown, its tip yellow. Anal appendages. Blackish brown, short.

Measurements (mm). Hindwing 20, abdomen including appendages 33.

Diagnosis. Males of this species share the black-and-white thorax pattern and all-white S9 with several other Protosticta, like P. socculus, P. linnaei and P. proboscis spec. nov., but the black line over the metapleural suture is narrower. The whitish horizontal bar on the frons is a helpful indicator, but it may not always be prominent. The diffuse pattern of the prothorax is also a good identification help. The shape of the posterior half of the paraprocts, scalpel-like in lateral view with raised cup at the base, and the trilobate broad cerci make identification in hand easy. Females are generally difficult, but the combination of diffuse brown horizontal bar on the frons, pale dorsal carina, all-white S9 and thoracic pattern with greenish shine dorsally and black-and-white stripes laterally is a solid indicator.