(Figs. 31–41, 64–66)
Diagnosis. The only Neotropical species of the mutabilis group with the following combination of characters. Males with a very short antennal flagellum (length 0.40–0.47 mm); antennal ratio 0.91–1.21; gonostyus moderately short with slender rounded apex; right gonocoxal apodeme broadly fused with paramere, left apodeme not fused with paramere; apical section of paramere J-shaped, tapering distally, tip sharply pointed; aedeagus with deep basal arch, posterolateral arms with pointed apices, without mesal subapical toothlike process. Females with very short antennal flagellum (length 0.31–0.33 mm), flagellomeres 2–12 moniliform, 13 slightly elongate with abruptly tapered apex, antennal ratio very small (0.65–0.71); wing broad with very short costa, costal ratio 0.23–0.25; subgenital plate very broad, ovoid with small narrow lumen, posteromedian margin rounded, posterolateral arms stout, nearly straight; spermatheca small (35 x 28 µm), ovoid, with numerous surface punctuations, with a stout, recurved neck.
Male. Head (Fig. 31). Brown. Eyes contiguous for a distance equal to the width of 3–4 ommatidia. Antennal flagellum very short; flagellomeres 2–9 rhomboid, 10–13 elongate, 10 longest, 13 broadest; flagellomeres 2–12 with single whorl of long sensillae chaetica comprising the dense plume that extends to near apex of flagellomere 12; antennal ratio 0.91–1.21 (0.98, n=12); flagellum length 0.40–0.47 (n=12) mm. Frontal sclerite rhomboidal with a slender posterior extension. Clypeus with 4 pairs of setae. Palpus (Fig. 32) pale brown; segment 3 slender, as long as 4+5 combined with scattered capitate sensillae on inner surface; palpal ratio 2.85–4.20 (3.56, n= 13). Thorax. Dark brown; scutellum with 6 large, 2–3 smaller setae. Wing (Fig. 33) moderately slender; membrane hyaline with moderately dense macrotrichiae; veins brown; 2 nd radial cell reduced to a suture, with gap between apices of costa, radius; fork of CuA 1 at level of apex of 2 nd radial cell; without a well-defined anal lobe; wing length 0.57–0.70 (0.65, n=12) mm, width 0.22–0.26 (0.23, n=12) mm; costal ratio 0.41–0.45 (0.43, n=12). Abdomen. Dark brown. Genitalia (Figs. 34, 64–66). Tergite 9 broad on proximal half, slightly tapering distally, apex broad, truncate, extending near apex of gonocoxites; apicolateral processes slender, widely separated, apex triangular, with subapical medium-sized, stout seta; cercus small, located at base of apicolateral process with 2–3 setae. Sternite 9 (Figs. 34, 64) short, 0.26 length of greatest width; posteromedian portion convex. Gonocoxite 1.7 x longer than broad, apicomesal surface with group of dense, moderately long setae; gonostylus 0.82 length of gonocoxite, broad at base, gradually tapering distally to pointed tip. Paramere and gonocoxal apodemes (Figs. 34, 65) asymmetrical; gonocoxal apodemes very broad, recurved 90°, right apodeme broadly fused with paramere, left apodeme not fused with paramere; paramere main body straight, apical section J-shaped, tapering distally, tip sharply pointed. Aedeagus (Figs. 34, 66) heavily sclerotized, 0.40 length of greatest width; basal arch deeply curved, extending 0.50 of total length; basal arms short, stout, apices slightly recurved, tips rounded; posterolateral arms slightly convergent, each with more lightly sclerotized, tapered distal portion, tips bluntly pointed.
Female. Head (Fig. 35). Brown. Eyes contiguous for a distance equal to the width of 3–4 ommatidia. Antennal flagellum dark brown, very short; flagellomeres 2–12 moniliform, 13 slightly elongate; antennal ratio 0.65–0.71 (0.69, n=3); flagellum length 0.31–0.33 (n=2) mm. Frontal sclerite (Fig. 36) rhomboidal, with a slender, very long ventral extension. Clypeus (Fig. 37) with 5 pairs of setae. Palpus (Fig. 38) light brown; segment 3 about as long as 4+5 combined with scattered capitate sensillae on inner surface; palpal ratio 2.11–2.57 (2.35, n=4). Thorax (Fig. 39) pale brown. Scutum with 3 longitudinal dark brown stripes; scutellum paler with 6 large, 4 smaller setae. Legs pale brown, tarsomeres 5 infuscated; hind tibial comb with 6 spines; prothoracic tarsal ratio 2.00–2.40 (2.12, n=4), mesothoracic tarsal ratio 1.92–2.09 (2.02, n=4), metathoracic tarsal ratio 2.00–2.28 (2.17, n=4). Wing (Fig. 40) broad; membrane hyaline with dense macrotrichiae; 2 nd radial cell reduced to a short suture; apices of costa, radius at slight acute angle; fork of CuA 1 at level of base of 2 nd radial cell; wing length 0.56–0.60 (0.58, n=4) mm, width 0.25–0.28 (0.26, n=4) mm; costal ratio 0.23–0.25 (0.24, n=3) mm. Halter brownish. Abdomen. Pale brown, tergites darker. Subgenital plate (Fig. 41) broad, ovoid, with small narrow lumen, posteromedian margin rounded; posterolateral arms stout, nearly straight. Spermatheca (Fig. 41) small (35 x 28 µm), ovoid, with numerous surface punctuations, neck stout, recurved, length 10 µm.
Distribution. Curaçao.
Type material. Holotype male, labeled “ Curaçao, Christoffel Nat. Pk. Christoffelberg, trailhead parking, 12°20ʹ40.63ʹʹ N, 69°67ʹ11.38ʹʹ W, 9-XI-2014, M. C. Thomas, BL trap; allotype female same data as holotype except 12°20ʹ40.29ʹʹ N, 69°06ʹ20.59ʹʹ W, R. Turnbow (deposited in FSCA). Paratypes, 12 males, 3 females: same data as holotype, 5 males; same data as allotype, 1 female; same data as allotype except 12°20ʹ10.63ʹʹ N, 69°06ʹ59.70ʹʹ W, 2 males, 1 female; same data as holotype except, N car route, Thorn scrub area, 13-XI-2014, M. C. Thomas, Black- light trap, 2 males, 1 female; Christoffel Nat. Pk., N car route, 4-XII-2015, M. C. Thomas, Blacklight trap, 1 male; same data as allotype except, Christoffel Nat. Pk., 12°20ʹ10.63ʹʹ N, 69°06ʹ59.70ʹʹ W, 9- XII-2015, R. Turnbow, BL trap, 2 males
Derivation of specific epithet. The specific epithet is named after the type locality, Curaçao, the only place in the Caribbean region this species is presently known from.
Discussion. This new species is somewhat similar to D. recurva n. sp. and D. cyrtostyla n. sp. See the key and discussion sections of these two species for characters to distinguish them from D. curacaoenis n. sp.