Bassus gracilicornis Nees von Esenbeck, 1812: 206. Type: lost.
Tanycarpa gracilicornis: Foerster 1862: 265, Wharton 1980: 73 (discussion), Tobias and Jakimavicius 1986: 180 (in key to European species), Chen and Wu 1994: 139 (redescription, range extension), Belokobylskij 1998: 208 (in key to species from eastern Russia).
Material examined. China, Ningxia: Liupanshan, Wanghuanan, 5 ♀ 7 ♂ 20 –VIII– 2000, Zhihui Lin (1 ♀ 1 ♂ USNM); 1 ♀ 3 ♂ same data as previous except Quanxiu Shi (1 ♂ USNM); 4 ♀ 4 ♂ same data as previous except Qinge Ji (1 ♀ 1 ♂ USNM); 4 ♂ same data as previous except Jianquan Yang (1 USNM); 1 ♀ 1 ♂ Guanghong Liang; 1 ♂ Migangshan, 22 –VIII– 2000, Zhihui Lin; 1 ♀ Jingyuan, 15 –VIII– 2000, Quanxiu Shi; China, Hubei: 1 ♂ Shennongjia, 22 –VIII– 2000, Juchang Huang (all at FAFU except as noted for USNM).
Diagnosis. Antenna with 30–40 flagellomeres; frons almost flat, glabrous; mandible 1.40–1.60 × longer than wide; midpit long and narrow; scutellar sulcus deep, wide, with 1 strong longitudinal carina, adjacent to carina rugose or with just a few rugae; notauli distinctly crenulate anteriorly, obliterated posteriorly; midpit long and narrow; mesoscutal lobes with dense setae medially but glabrous laterally; propodeum with distinct longitudinal ridge in basal 1 / 4 – 1 / 5 that splits into two transverse ridges, two longitudinal ridges extend posteriorly from tubercles and form closed glabrous areola; 1 cu-a small, postfurcal; legs yellow except apical 1 / 4 of hind tibia and entire tarsus slightly to strongly infuscate; pterostigma brown; T 1 brown, metasoma except T 1 brownish yellow to brown. Body 3.08–3.60 mm.
Distribution. Austria; Belgium; Canada (Alberta and Ontario); China (Fujian, Ningxia, Hubei); Czechoslovakia (former); Finland; Germany; Hungary; Ireland; Italy; North Korea; Poland; Russia (Primor'ye Kray, Sakhalin Oblast, Saint Petersburg); Switzerland; United Kingdom; USA (Alaska).
Remarks. Tanycarpa gracilicornis is widespread and is morphologically similar to T. mitis and T. similis based on the filiform apical three antennal flagellomeres and presence of a mesoscutal midpit. However, T. gracilicornis has 30–40 flagellomeres, T. mitis has 24–27 flagellomeres, and T. similis has 25–29 flagellomeres. As for T. mitis and T. similis, they are separated primarily using the median longitudinal ridge of the propodeum and the fore wing 2 nd submarginal cell. Tanycarpa mitis has a longitudinal ridge in the basal 1 / 3, and the 2 nd submarginal cell longer; T. similis lacks a longitudinal ridge, and the 2 nd submarginal cell is shorter. In T. gracilicornis the propodeum has a distinct longitudinal ridge in the basal 1 / 4 – 1 / 5, and the 2 nd submarginal cell is shorter as in T. similis.