Very similar to recent and Neogene species of Lygistorrhina by the very long, slender proboscis and palpi; anterior ocellus small to minute; laterotergite lobate and setose; stem of M and bases of M1 −M2 fork absent; R5 without setae. Differing from other species of the genus by lack of concavity on lateral surface of metacoxa, and setae on laterotergite not in a row on posterior margin.
Head: Subspherical, occiput and vertex short setose. Eyes with facets round and equal in size, ommatidia very densely set. Postocular setae not present or not visible, interocular setae short, sparse, very fine. Eyes emarginate just lateral to antennal base; emarginate area bare of ca. one row of facets. Number of ocelli three, nearly in a transverse line, middle ocellus significantly smaller than lateral ocelli. Frons and face broad; extensive membranous area ventral and lateral to antennal bases, with small sclerotized condyle. Clypeus slightly crescentic, with marginal setae. Palpi one-segmented, long, 0.7× the length of proboscis, tapered apicad to fine tip, with a single row of setae. Proboscis evenly curved (of medium length), (very long in Tad-442, Tad-492) about 2.2× (3.3×) as long as head high, with fine short setae. Oral margin slightly protruding; deeply incised, with clypeus nestled fully within. Labrum long triangular, with rounded apex, without setae. Antenna with 14 flagellomeres. Scape bulbous; pedicel subcylindrical, broadened apically, 1.8× wider than flagellomeres. Flagellomeres 1–13 cylindrical, about 1.2× longer than broad. Terminal flagellomere evenly tapering to rounded apex, only slightly longer than previous ones and 1.5× longer than broad.
Thorax (Fig. 6D): Scutum dome-shaped, strongly arched, entirely covered with setae of medium length; acrostichals long, longer setae on posterolateral surface of scutum. Scutellum with a row of long setae on posterior margin. Thorax in lateral view short (anterior to posterior margins), tall/deep (dorsal to ventral margins). Laterotergite well produced posteriad into a lobe, with long setae over broad surface (not in marginal row).
Legs: Coxae virtually equal in length. Fore coxae setose anteriorly, mid and hind coxae with sparse setae laterally. Fore tibia evenly covered with short setae, with one tibial spur, not expanded towards apex, approximately equal in length to fore femur. Tibiae and tarsi with microtrichia in longitudinal rows. Tibial spurs 1 : 2 : 2; anterior midtibial spur 0.3× length of other spur. Hind tibia with apico-lateral comb of thick, short setae (presence/absence of depression here not observable). Hind coxa without lateral concavity. Tips of all claws pointed, none blunt.
Wing: Fairly short and broad, length/width 2.13, apex rounded but not extensively so. R1 setose, R5 without setae, other veins bare. Costa extending to approximately 2/3 distance between R5 and M1. Sc ending at C. R1 slightly curved posteriorly, apex ending beyond middle of wing. R5 moderately sinuous in apical third. M stem and bases of M1+2 fork lost. M2 extends slightly more basally than M1. CuP very close and parallel to stem of CuA; apex of CuA strongly curved, almost perpendicular to stem of CuA. Anal lobe well developed.
Abdomen: That of female long, slender, tubular, cerci two-segmented
Female. Head height: 0.29 mm; proboscis length: 0.90 mm; palpus length: 0.61 mm; antenna length: 0.58 mm; body length without head: 2.17 mm; wing length from humeral vein: 1.32 mm.
Tad-492: Measurements: Head height: 0.38 mm; proboscis length: 0.90 mm; palpus length: 0.45 mm; antenna length: 0.68 mm; body length without head: 2.64 mm; wing length from humeral vein: 1.83 mm.
Tad-888: Measurements: Head height: 0.22 mm; antenna: 0.5 mm; proboscis: 0.5 mm; palpus: 0.35 mm.