Male: Head: slightly elongate, in frontal view slightly taller than wide, triangular in profile, wider at axis of pedicel than at axis of vibrissa. Height of gena 0.3x-0.4x eye height. Inner vertical setae stout, incurved and medially crossed, nearly half of eye height; outer vertical setae short to absent. Ocellar triangle extending into occiput, ocellar setae strong and proclinate. Fronto-orbital plate with lowest frontal seta situated at level of base of pedicel. Frontal vitta prominent and inwardly pinched, at narrowest point narrower than ocellar triangle. Vibrissae crossed, level with lower facial margin. Facial ridge bare. Antennal insertion situated below middle level of eye. Pedicel with short dorsal setae equal in length to pedicel; postpedicel short and slightly bean-shaped, twice as long as pedicel, short and parallel-sided, rounded at apex. Arista elongate, bare and filiform. Eyes haired. Thorax: prosternum bare. Thoracic chaetotaxy: 3:3 acrostichal setae; 3:3 dorsocentral setae; 2:2 intra-alar setae; 2:2 supra-alar setae; 4 postpronotal setae; 3 katepisternal setae, 2 anterior and 1 posterior to suture. Scutellum densely haired, strong pair of medially crossed preapical setae and 3 pairs of marginal setae. One pair of weak but differentiated widely-spaced scutellar discal setae. One strong anepimeral seta stronger and longer than others, but not extending beyond margin of upper calypter. Meron with 6-10 regular setae. Lappets of posterior spiracle appearing as a fringe of hairs of equal length surrounding the spiracle leaving a central "u"-shaped opening. Postmetacoxal bridge unsclerotized. Legs: anteroventral surface of forecoxa gold tomentose with several strong setae, ventral surface bare; anterior tibia with a regularly-sized fringe of equally-spaced setae along anterodorsal surface, posterodorsally with two strong setae. Posterior tibia with 3 large strong posteroventral setae, posterodorsal surface with a ragged irregular fringe of 4–5 strong setae. Tarsal claws black, pulvilli elongate subequal to length of tarsal claws. Wing: costal spine absent. R₄₊₅ at base with 2–3 setulea dorsally and 1–2 setulae ventrally. Bend of vein M obtuse, vein terminating in wing margin. Stub of CuA₁ terminating in wing margin, 1.9x length of cross-vein dm-cu. Abdomen: abdomen elongate, almost 2x as long as wide; mid-dorsal depression of T1+2 reaching to hind margin; median marginal setae on T3 and complete rows of marginal setae on T4–T5 (reduced on T5); T3–T5 each with one pair of median discal setae. Terminalia: cercus sharply pointed and strongly tapered, basal section of syncercus 1/3 as long as apical section; strongly curved when viewed laterally; surstylus narrow and scythe-like in lateral view, apices unusually sharp; surstyli angled medially in dorsal view; surstylus 1.6x as long as cercus. Phallus distinctly hinged as in the remainder of the Dexiinae.

Female: As in male with the following exceptions: width of head at widest point 4.2 times width of vertex (in frontal view), profile 1.6x wider at axis of pedicel, than at axis of vibrissa, frontal view head height 1.17x head width. Height of gena 0.43x eye height. Two proclinate orbital setae, hind one slightly shorter than anterior. Postpedicel longer than in males nearly 2.4x as long as pedicel. Height of gena longer in females than in males. Thorax: Scutellum densely haired, strong pair of inwardly crossed preapical setae and 3 pairs of marginal setae. Meron with 6-10 regular setae. Legs: tarsal claws black, pulvilli short approximately 0.5x length of tarsal claws. Wing: as in males. Abdomen: abdomen elongate but slightly more globose than male; median marginal setae on T3 and complete row of marginal setae on T4–T5; T3–T5 each with one pair of median discal setae. Terminalia: not examined.

Our diagnosis of the new genus suggests it belongs to the tribe Uramyini, based on the following combination of character states which it shares with its tribemates (Uramya Robineau-Desvoidy, Itaplectops Townsend and Thelairaporia Guimaraes): frontal setae extending only to the base of the pedicel, bare prosternum, the short fine anepimeral seta not reaching the midpoint of the lower calypter, vein R₄₊₅ ending at wing margin, elongated "cylindrical" body plan, the "u"-shaped lappets of the posterior spiracle and the distinctively hinged and "L"-shaped terminalia with the end of the basiphallus extending beyond the hinge with the distiphallus (Townsend 1936, Guimarães 1980, Fleming et al. 2015, Fleming et al. 2017). Chorotegamyia can be differentiated from the rest of the Uramyini by the following combination of character states: presence of proclinate orbital setae only in females, short weak vertical setae, two postsutural supra-alar setae, only one pair of discal setae on T3–T5 and mid-dorsal depression on T1+2 extending almost to tergal margin.

Chorotegamyia gen. n. is named with reference to the Chorotega Indian tribe historical residents of the province of Guanacaste in North Western Costa Rica.

Costa Rica, ACG, Guanacaste Province, 295 m elevation.

Male, length: 11–12 mm (Fig. 2). Head (Fig. 2a, b): subtriangular in profile, width of head in frontal view at widest point 4.2x width of vertex, in profile 1.44x wider at axis of pedicel than at axis of vibrissa; head height in frontal view 1.1x head width. Fronto-orbital plate and parafacial uniformly colored deep rich gold, extending to post-occiput, with a single row of medioclinate frontal setae, with a few short black setae interspersed throughout, lowest frontal seta level with base of pedicel; inner vertical setae strong, incurved and medially crossed, 0.4x height of eye; outer vertical setae short near absent. Fronto-orbital plate strongly tapered, at vertex 0.33x as wide as at base of antenna. Ocellar triangle gold tomentose, terminating dorsally in a sharp triangle in occiput; ocellar setae strong and proclinate. Base of antennae situated below middle of eye. Pedicel brilliant orange, with short dorsal setae of vaguely equal length to pedicel; postpedicel short and slightly bean-shaped, nearly 2x as long as pedicel, short and parallel-sided, rounded at apex. Arista elongate, bare and filiform, basally orange and slightly thickened. Parafacial gold, bare; gena 0.3x eye height, haired; facial ridge bare. Vibrissae crossed, level with facial margin. Occiput of head slightly convex, occipital setulae black along outer margins, yellow medially. Palpus short yellow and digitiform with few sparse setulae throughout. Thorax (Fig. 2c, d): disc of thorax dark grey almost black, marginally (outside of intra-alar row of setae) with golden tomentosity; lateral view of thorax grey tomentose with gold accents. Thoracic chaetotaxy: 3:3 acrostichal setae; 3:3 dorsocentral setae; 2:2 intra-alar setae; 2:2 supra-alar setae; 4–5 postpronotal setae; 3 katepisternal setae (two anterior and one posterior to suture). Scutellum densely haired, strong pair of inwardly crossed preapical setae and 3 pairs of marginal setae. Legs (Fig. 2d): black ground color, tibiae yellow ground color, but densely hirsute so as to appear black; foreleg, coxa with golden tomentum along anterior surface laden with several strong setae. Wing (Fig. 2c): slightly infuscate along costal margin extending to and including R₄₊₅, brown veins, costal spine absent; basicosta dark brown; calypters pale yellow translucent, marginally setulose, upper calypter ~1.5x as large as lower calypter. Abdomen (Fig. 2c, d): abdomen elongate, 2x as long as wide; ST1+2 black, T3 brown tomentose, T4–T5 golden tomentose, with a moderate vestiture of short decumbent black setae; T4 with a mid-dorsal darkened stripe reaching a darkened band along tergal margin occupying 0.16x of tergite; T5 entirely gold reaching apex; mid-dorsal depression of T1+2 reaching to hind margin; median marginal setae on T3 and complete row of marginal setae on T4, marginal setae irregular on T5 medial pair not reaching tergal margin, making their appearance confused as medial discal setae; T3–T4 each with one distinct pair of short median discal setae. Terminalia (Fig. 3): inner margin of sternite 5 pollinose, appearing slightly darker than surrounding cuticle; posterior lobes of sternite with short, stout setae interspersed with 5–8 longer setae closer to apical margins; wide V-shaped median cleft, 0.5x length of sternite from lobe apex to base (Fig. 3d). Cercus sharply pointed and strongly tapered, basal section of syncercus 0.4x as long as apical section; strongly curved when viewed laterally and with a sharp upward hook at its tip (Fig. 3b). Surstylus narrow and scythe-like in lateral view, apices sharp; both surstyli and syncercus heavily sclerotized, appearing black despite clearing; surstyli angled inwards in dorsal view (Fig. 3a); almost parallel; surstylus 1.6x as long as cercus. Phallus distinctly hinged as in the remainder of the Dexiinae; dorsal process of basiphallus extending beyond joint with distiphallus. Postgonite elongate, extending well beyond hinge of distiphallus (Fig. 3c).

a

b

c

d

Figure 2.

Chortegamyia aureofacies sp. n. habitus images; male, holotype n. DHJPAR0040802.

a: frontal view of head  
b: lateral view of head  
c: dorsal view  
d: lateral view  

a

b

c

d

Figure 3.

Chorotegamyia aureofacies sp. n. terminalia images; male, paratype n. DHJPAR0040795.

a: caudal view  
b: lateral view  
c: oblique lateral view  
d: sternite 5, ventral view  

Female, length: 12–13 mm (Fig. 4). Head (Fig. 4a, b): as in males with the following exceptions: width of head at widest point 4.2x width of vertex (in frontal view), profile 1.6x wider at axis of pedicel, than at axis of vibrissa, frontal view head height 1.17x head width. Height of gena 0.43x eye height. Fronto-orbital plate with 1–2 pairs of proclinate orbital setae and one hindmost pair of reclinate orbital seta, hind proclinate orbital seta slightly shorter than anterior; sparsely setulose with two sparse rows of setulae outside of frontal setae; not tapered, at vertex subequal to width at base of antenna. Postpedicel short and slightly bean-shaped, slightly longer than in male, nearly 2.4x as long as pedicel. Arista basally brown and slightly thickened. Height of gena 0.45x height of eye. Palpus short yellow and slightly spathulate with few sparse setulae throughout. Thorax (Fig. 4c, d): disc of thorax covered in light golden tomentum with the exception of 4 wide dorsal stripes, inner pair reaching midway to second postsutural intra-alar. Thoracic chaetotaxy as in males. Legs: as in males. Wing: as in males. Abdomen (Fig. 4c, d): dark bronze pollinose on T3 and T4, T5 entirely golden pollinose, whole abdomen significantly darker than male; mid-dorsal dark stripe evident on T3–T5; darkened band on both T3 and T4 occupying 0.16 of the tergite along the posterior margin; in lateral view, T3–T4 silver pollinose; abdomen elongate but slightly more globose than male, 1.5x as long as wide; median marginal setae on T3 and complete row of marginal setae on T4–T5; T3–T5 each with one pair of median discal setae. Terminalia: not examined.

a

b

c

d

Figure 4.

Chorotegamyia aureofacies sp. n. habitus images; female, paratype n. DHJPAR0040804

a: frontal view of head  
b: lateral view of head  
c: dorsal view  
d: lateral view  

Chorotegamyia aureofacies sp. n. is a medium-sized reddish-gold fly. It can be recognized easily within the tribe by the brilliant gold coloration of the fronto-orbital plate and parafacials, the two postsutural supra-alar setae and the distinctive gold ocellar triangle (Fig. 5).

Figure 5.  

Occipital view of Chorotegamyia aureofacies sp. n. highlighting distinctive gold ocellar triangle reaching posteriorly into occiput; image from male holotype.

Chorotegamyia aureofacies sp. n. from the Latin adjective, “aurus” for gold and the noun "facies" for face, with reference to its brilliant gold tomentose head.

Costa Rica, ACG, Guanacaste Province, 295 m elevation.

Chorotegamyia aureofacies sp. n. has been reared nine times from a single species of Lepidoptera, collected in old secondary succession dry forest, from a massive outbreak of caterpillars of Norape nigrovenosa (Druce, 1906) (Megalopygidae). This is the only record of this species of fly out of 4,113 rearings of megalopygid caterpillars in the ACG inventory (1978-2019), of at least 20 species of caterpillars from all ACG ecosystems, 180 of these caterpillars being parasitized by Tachinidae of at least 23 species. This species of caterpillar burrows deep into the soil to spin a very tough double-walled cocoon and the fly larva emerges from the prepupal cadaver to make its puparium inside the moth cocoon next to the cadaver. The batch of caterpillars that yielded the nine C. aureofacies specimens (one per caterpillar) was also parasitized by three other species of Tachinidae (Lespesia, Avibrissosturmia, and Hyphantrophaga).