Perilampus hyalinus species group

P. hyalinus species group sensu Smulyan (1936) and Darling (1996).

Description. FEMALE. Color: head and body entirely or at least partially brightly iridescent blue, green, violet, or cupreous (Fig. 2A–C).

Head: in anterior view weakly transverse, slightly wider than high, HW/HH 1.2–1.3; slightly wider than pronotum, HW/PW 1.1–1.2. Frontal carina: distinct, extended from posterior margin of median ocellus (Fig. 2A) to near lower eye margin; in dorsal view narrow around median ocellus. Ocelli: median ocellus in line with lateral ocelli or only slightly advanced. Eye: slightly shorter than head height, EH/HH 0.6–0.7. Vertex: rounded behind. Occiput: with vertical groove below vertex, with subparallel costulae; occipital carina absent. Malar space: with oblique striae obliterating malar sulcus (Fig. 2B). Clypeus: weakly transverse to strongly transverse, CW/ CH 1.3– 1.6; lateral sulci straight or weakly curved, strongly divergent; with small and indistinct tentorial pits; epistomal sulcus concave, deeper and more distinct than lateral sulci; ventral margin concave or nearly straight. Supraclypeal area: subquadrate; shorter and narrower than clypeus, SCH/ CH 0.5–0.6. Scape: length about 0.6× EH; narrow throughout; pits absent or if present distad covering no more than 0.2× scape length. Flagellum: anellus transverse, AL/PL about 0.3; Fu1 subquadrate, Fu1L/Fu1W 1.0–1.1; subequal to or slightly longer in length than pedicel, Fu1L/PL 1.0–1.3; Fu2 subquadrate or transverse, Fu3–Fu7 transverse; clava 4-segmented, C1–3 as long dorsad as ventrad, with distinct terminal button (C4).

Mesosoma: slightly longer than wide, ML/MW 1.2–1.3. Pronotum: carinulate; short, PN/MSC about 0.2; shorter along midline, 0.5–0.7 length laterad; anterior margin sharp, all rows of punctures on same plane. Lateral panel of pronotum: without flange or with flange below level of mesothoracic spiracle in posterior oblique view; anterior margin sharp, all rows of punctures on same plane. Prepectus: wide and triangular; differentiated from pronotum with distinct suture; ventral strap short, without row of alveolae; central area of lateral panel smooth, with foveae along dorsal and posterior margins. Mesoscutum: midlobe without tubercle; notaulus distinct and continuous, uninterrupted by sculpture of mesoscutum. Mesoscutellum: without tubercle; slightly longer than mesoscutum, SC/MSC 1.2–1.3; strongly vaulted, frenum ventrad and not visible in the dorsal view. Axilla: with axillar shelf (Fig. 2C). Axillula: elongate and finger-like, AxL/AxH usually 2.0 or greater (Fig. 2C). Metanotum: short, length 0.4–0.5× length of propodeum along midline. Propodeum: width about 3× length along midline; submedian area smooth to weakly imbricate, with foveae or groove laterad median carina, delimited laterad and ventrad by complete plicae, dorsad by transverse band of foveae; callus with angulate process below spiracle, and alveolate-rugose, with alveolae sometimes obliterated below spiracle; nucha with transverse to arcuate rugae. Fore wing: elongate, WL/ WW 2.3–2.4; hyaline, with yellow or brown venation; parastigma swollen with weak equilateral triangular process; postmarginal vein 0.7–0.8× as long as marginal vein; stigmal vein 0.3–0.4× as long as marginal vein; stigma with weak uncus.

Metasoma: petiole short and straplike, with weak transverse wrinkles; petiolar flange short with ventral margin of upper area with shallow emargination mesad; antecostal sulcus transverse, with weak vertical carinae laterad and smoothened mesad; Mt2 with trapezoidal demarcation and shallow median groove, imbricate and wrinkled anteriad, and smooth posterad without lateral protuberances along midline, posterior margin straight and sparsely setose; Mt3 smooth.

MALE. As in female, except: color: mesonotum sometimes nearly entirely black or with cupreous iridescence. Eye: in dorsal view often more bulbous. Ocellus: often larger. Ocellar ratios LOD: POL: OOL: LOL: often shorter. Frontal carina: distance from lateral ocellus usually shorter. Lower face setae: as dense or denser around and below torulus. Malar space: MSL/EH often shorter. Flagellum: slightly wider. Scape: in anterior view weakly expanded distad, 1.3–1.4× width above radicle; with distinct pits on anterior surface; pitted surface not swollen in lateral view. Aedeagus: without a pair of lateral spines.

Diagnosis. The P. hyalinus species group is characterized by brightly iridescent coloration (Fig. 2A–C), a distinct frontal carina extended from the posterior margin of the median ocellus (Fig. 2A cf. Fig. 2D) to near the lower eye margin, oblique costae obliterating malar sulcus (Fig. 2B cf. Fig. 2E), a carinulate pronotum (Yoo and Darling 2024, fig. 2H), a distinct and uninterrupted notaulus (Yoo and Darling 2024, fig. 2H), an axilla with an axillar shelf (Fig. 2C cf. Fig. 2F), and an elongate, finger-like axillula (Fig. 2C cf. Fig. 2F). The P. platigaster species group has a similar structure of the frontal carina, axilla, and axillula, but is distinguished by having a malar sulcus (Fig. 2E) and general body color that is black with or without weak iridescent reflections.