Trichacis acarinata Arias-Penna & Masner, new species

Figures 1 A–1F, 21A

Female. Body length: 2.80 mm (holotype).

Dark brown; A1–A6 yellow; A7–A10 brown; mandible yellow with base and apex brown; leg yellow; hind coxa brown; fore wing infuscate.

Head, in dorsal view, 2.2 times as wide as long; EH <IOS; interocellar area smooth; OOL> LOL; antennal clava 3-segmented; A1 not reaching vertex dorsal margin; A2–A5, A10 longer than wide; A6–A9 wider than long; base of mandible smooth; frons above torulus with transverse striae; interantennal process surpassing ventral border of torulus; clypeus exposed; clypeal margin concave medially; gena and vertex smooth; temple projection absent; hyperoccipital carina absent; distance between posterior ocellus and occipital carina line> OOL.

Mesosoma slightly arched; antero-admedian line absent; notaulus anteriorly incomplete; mesoscutum smooth; posteromedial region of inter-notaular area acute; parapsidal line present; central pronotal area smooth; specialized area of mesoscutellum heart-shaped; median projection of specialized area of mesoscutellum triangular; mesopleural carina incomplete (length of mesopleural carina/length of mesopleuron = 0.42); fore wing not surpassing apex of metasoma.

Metasoma distinctly elongate; combined length of T3–T6> T2; T1 wider than long; T2, T5 and T6 longer than wide; T3–T4 wider than long; T2 anteromedial area (i.e. between anterior pits) smooth and concave; T2–T3 smooth; anterior half of T4 with shallow punctuation; anterior half of T5 and T6 densely and deeply punctulate.

Male: Unknown.

Etymology. The name refers to the absence of hyperoccipital carina.

Diagnosis. Trichacis acarinata and T. punctata are characterized by the absence of a hyperoccipital carina. Trichacis acarinata differs from T. punctata by the following characters: combined length of T3–T6> T2; mesoscutum smooth; posteromedial region of inter-notaular area acute.

Material examined. Holotype: 1 Ƥ, COSTA RICA, Punt. San Vito, Biol. Sta. Las Alturas, 1500 m, May 1992, MT, P. Hanson (CNCI).

Holotype is deposited in CNCI.