Male (Fig. 84), length: 14–15mm. Head: head wider than thorax; vertex 1/2 head width; gena 1/4 of head height, 1/3 of eye height. Fronto-orbital plate silver-gray tomentose throughout, sometimes a bit lightly so along vertex, with 1–2 rows of frontal setae, populated with short black hair-like setulae intermingled with setae; ocellar setae absent; orbital setae absent. Parafacial, densely covered in same silver tomentum as on fronto-orbital plate, entire surface reflective and brilliant appearance; almost bare along parafacial outside facial ridge, with a few black setulae intermingled with facial ridge setae and extending just below lowest frontal setae; facial ridge setose along 2/3 of its length; gena covered in black setulae. Antenna, pedicel appearing orange almost covered in a silver tomentum; postpedicel dark brown almost black, 3–4X as long as pedicel; arista bare gradually tapering to a point at tip. Palps, dark yellow throughout and sparsely covered in short black setulae; tapering to a rounded apex, slightly sinusoid and clubbed shaped, devoid of setulae apically. Vibrissa approximately 1 pedicel length from facial margin. Thorax: black ground color along anterior portion, lightening to yellow orange along posterior 1/10th of scutum, with light pale-gray tomentum throughout, appearing dusty to the naked eye; scutellum ground color light brown, distinctly lighter than scutum, under microscope bronze tomentum throughout becomes visible; scutum with four narrow dorsal vittae, one outer pair, one inner pair, both broken at suture, inner pair extending only slightly beyond first post-sutural dorsocentral seta; lateral surface of thorax densely covered in long hair-like setulae, these setulae all black; chaetotaxy: 3–5 strong setae on postpronotum arranged in a line, acrostichal setae 4:4; dorsocentral setae 3:4; intra-alar setae 2:4 separated from dorsocentrals by 2X the gap separating dorsocentral setea from acrostichal setae; supra-alar setae 2:3; 4 katepisternal setae; scutellum, with 4–5 pairs of long marginal setae of subequal length; apical scutellar setae short erect, inserted slightly above plane of marginal setae; 1 complete row of scutellar discal setae just posterior to marginal setae. Wing: infuscate, slightly darkened brown at wing base, basicosta dark brown with only a slight accent of orange on margin; both upper and lower calypters also infuscate concolorous with remainder of wing; wing vein R₄₊₅ setose, bearing only 2–3 setulae at base; halteres orange. Legs: black overall; tarsal claws yellow-orange with black tips, with burnt umber pulvilli shorter than length of tarsal claws; anterodorsal row of setae on hind tibia irregular and not fringelike, with several longer stronger setae at least 2X as long as others. Abdomen: large and flattened globose, black to dark burgundy ground color; tomentum absent from T1+2, light dusting of bronze tomentum on T3 with only very slight gold tomentum along anterior margin, gold tomentum along anterior 15% of surface of T4, bisected medially by an area devoid of tomentum, brilliant gold tomentose throughout 95% of T5 reaching with black on hind margin of tergite; ventral surfaces of T3–T5 extremely densely hirsute but with no distinct sex-patches present, with light gold tomentum throughout; middorsal depression on ST1+2 reaching to hind margin of tergite; ST1+2 with 1 pair of median marginal setae, pairs of median marginal setae present on T3, and complete rows of setae on T4 and T5.

Male terminalia (Fig. 85) : sternite 5 with a deeply excavated median cleft along posterior edge, roughly Y-shaped, with soft shoulders, margins covered in dense tomentum; posterior lobes rounded apically, with a group of 4–5 strong setulae surrounded by many shorter weaker setulae. Anterior plate of sternite 5 approximately 1/2 length of posterior lobes; unsclerotized "window" on anterior plate of sternite 5 translucent, rectangular, slightly arcuate. Cerci in posterior view short triangular, equal to length of surstyli; pointed at apex, medially to fused along basal 2/3 of their length. Cerci in lateral view, inflated along basal 2/3rds, sharply tapered with anterior curved at apical 1/3, giving it a shallow hooked appearance; cerci setose along basal 2/3rds, underside of cerci setose along basal 2/3 of length. Surstylus in lateral view, wide rounded apically, straight along inferior margin; surstylus appearing not fused with epandrium; when viewed posteriorly surstyli convergent. Pregonite broad, well-developed, apically squared off, and blunt, with 5–6 marginal setulae. Postgonite, narrow, 1/2 as wide as pregonite, sharply pointed and curved at apex, bladelike, postgonite subequal in length to pregonite. Distiphallus broadly cone-shaped, with a slender median longitudinal sclerotized reinforcement on its posterior surface and a broad, anterolateral, sclerotized acrophallus, bearing a slight anterior hook on anterior surface near apex, 1.3X length of basiphallus.

Female (Fig. 86) length: 14–15mm, overall morphology as in male differing in the following traits: Head: bearing 2 rows of frontal setae and 3–4 pairs of proclinate orbital setae in addition to single pair of reclinate orbital seta; gena 1/3 of head height, 2/5 of eye height. Abdomen: gold tomentum covering anterior 10% of surface of T4, bisected medially by an area devoid of tomentum, and all of T5, much denser than in males; T4 bearing a narrow median black stripe bisecting yellow band; slightly more globose than males.

Belvosiapetronariosae sp. n. can be distinguished from all other Belvosia by the following combination of traits: yellow setulae on gena, orange basicosta, abdominal ground color orange, postocular margin of head gold tomentose.

Belvosiapetronariosae sp. n., is named in honor of Sra. Petrona Rios in recognition of her decades of being part of the Parataxonomist Program of Area de Conservación Guanacaste (http://www.acguanacaste.ac.cr) in northwestern Costa Rica (Janzen and Hallwachs 2011). Interim species-specific name included in previously circulating databases and publications, Belvosia Woodley16.

Costa Rica, ACG, Guanacaste Province, 280–760m elevation.

Belvosiapetronariosae sp. n. has been reared 79 times from one species of Lepidoptera in the family Saturniidae, Arsenuraarianae Brechlin & Meister, 2010 (N=79), in cloud forest, rain forest, dry forest, and dry-rain lowland intergrade.