Lasius nigrescens Stitz 1930

Seifert, Bernhard, 2020, A taxonomic revision of the Palaearctic members of the subgenus Lasius s. str. (Hymenoptera, Formicidae), Soil Organisms 92 (1), pp. 15-86 : 75

4.4.48 Lasius nigrescens Stitz 1930

Lasius emarginatus var. nigrescens Stitz 1930

[type investigation]

Type material: Lectotype (des. E.O. Wilson) and 4 paralectotype gynes labelled ”West-Pamir, VII-IX 28, leg. Reinig, Maz, 3800 m, 15.-19. VIII“; depository ZM Berlin.

Comments. The types series consists of alate gynes obviously caught during nuptial flight. The missing knowledge on worker morphology in Lasius nigrescens and missing knowledge on gyne morphology in the Himalayan-Tibetan species makes the taxonomic assessment difficult. Considering the correlations that usually exist between gyne and worker morphology in Lasius ( Seifert 1992) , the worker of L. nigrescens is expected to have a long scape (SL/CS 900 perhaps 1.06), an average head length index (CL/CW 900 perhaps 1.07), and numerous setae on underside of head and hind tibiae. Pictures of the type gynes are shown in antweb. org under the specimen identifiers ANTWEB1008433 and ANTWEB1008434. I present here the data of 5 investigated type gynes: CS 1411 ± 17 [1392, 1432]; CL/ CW 0.883 ± 0.010 [0.872, 0.896]; SL/CS 0.870 ± 0.010 [0.856, 0.879]; nGu 32.0 ± 5.6 [27, 40], nOcc 29.1 ± 1.6 [27, 31]; nGen 15.2 ± 4.2 [12.5, 20.0]; GuHL/CS 0.112 ± 0.005 [0.107, 0.16]; PnHL/CS 0.147 ±0.005 [0.143, 0.152]; sqPDCL 4.68 ± 0.17 [4.49, 4.89]; ML/CS 2.168 ± 0.036 [2.130, 2.223]; MH/CS 1.146 ± 0.026 [1.122, 1.189]; MW/ CS 1.329 ± 0.006 [1.322, 1.333].