S. Mahunka szerk.: Folia Entomologica Hungarica 44/1. (Budapest, 1983)

Commonest species of the group with wide distribution in the alpine zone of the Caucasian Mountains. Size, colour, and form of pronotum somewhat variable, therefore easily may be mixed with the nearest species. The original description of MOTSCHULSKY is very short and vague "Nebria tenella, am meistens der N, angusticollis Bon ähnlich, doch etwas kleiner, besonders gestreckter. Farbe ein glänzendes Schwarzbraun. (Alpaeus Bon.). Alp. Cauc. Tuschetia", p. 72. Almost all species of the N. caucasica group correspond to this description, and old authors determined this species as N. caucasica Mén. On the basis of such identification in old collections BANNINGER erroneously reduced N. tenella to synonyms of N. caucasica

. This synonymy was repeated by CSIKI (1927: 376) and KIRSHENBLAT (1932: 93). The latter author had seen the types of MOTSCHULSKY, but did not find the type of N. caucasica Mén. Lectotype, cf, designated here, bears two labels: "Alpaeus tenellus mihi, Alp. Cauc." and "Digverdi bei B. Samkirno, 26 Juli" (ZMM). Paralectotypes: 2 g from the same series without labels (ZMM); 1 cf, 2 g with golden square and printed text on red paper "Alp. Caucas." (ZIL). In the same work, "Die Käfer Russlands", MOTSCHULSKY described the second species of Nebria from Tuschetia. In the original description the text reads as: "Nebria longicornis gleicht in der Gestalt und Farbe der N. brunnea Dej., hat aber eine mehr glänzende Oberfläche, ist schmäler und mit längeren Fühlern (Alpaeus Bon.). Alp. Cauc. Tuschetia", p. 71. BÄNNINGER incorrectly considered it as synonym of N. diaphana

. Then KIRSHENBLAT rehabilitated their independence, but considered it as distinct species. N. longicornis Mötsch, was described based on series of small (8.5-10.0 mm) and narrow specimens. Investigation of extensive material from the Caucasus has shown that in all general characters N. longicornis Mötsch, corresponds to N. tenella Mötsch, and must be reduced to synonymy. In spite of the relative priority of N. longicornis I choose the name N. tenella which belongs to the more common and typical form. In the collection of MOTSCHULSKY (ZMM) there are 3 g, glued on to one piece of cotton and bear the label "Berg Massara in dem Tuschen Alpen, august", which are designated here as lectotype (specimen on the left) and paralectotypes. Other paralectotypes: 1 cf with label "Alp. Massara, 28 aug." (ZMM); 1 g with golden square and red label "Alp. Cauc." (ZIL). REITTER (1888) described from Fischt Mt. a series of Nebria with infuscated femorae and intermediate segments of antennae, which he called N. planulata f. tristicula. The type series was not uniform and consists partly from N. tenella Mötsch, and partly of N. retrospinosa Heyd. (= N. planulata Reitt.). One female in the collection of REITTER (HNHM) with label "Caucas occ, Circassien, LEDER, REITTER", designated here as lectotype, corresponds to N. tenella Mötsch. K. DANIEL (1903) had the same specimens from the type series, which is clear from his remark about plurisetose sternits, characteristic for N. tenella but not for N. retrospinosa

. Paralectotypes, 1 cf, 2 g (ZIL) with the same labels, moreover one specimen with label "

Nebria var. tristicula Reitt., 89, Ca. 64", and the second specimen with label "

N. planulata R. v. tristicula Rttr, Ca./Rttr, 88/" by handwriting of A. P. SEME NOV-TIAN-SHANSKIJ. All these specimens correspond to N. retrospinosa Heid, (see below). N. tenella Mötsch, is divided into 3 subspecies, two of them described as new. 1. N. tenella tenella Mötsch. Body dark piceous, legs, antennae and palpi reddish piceous to dark red, sometimes intermediate segments of antennae and femorae infuscated. Pronotum (fig. 80) 1.29-1.45 times as wide as long, at sides slightly rounded and before acute hind angles hardly sinuated, apical angles short and rounded. Elytra elongate ovate, 1.47-1.59 times as wide as pronotum, 1.61-1.76 times as long as wide, widest in apical third, shoulders slightly prominent, basal border straight or somewhat curved, forming with lateral one very obtuse angle. Striae rather deep, distinctly punctate, intervals slightly convex, interval 3 without setiferous pores, rarely with 1-2 small pores apically, scutellar pores as a rule absent, rarely present. Sternits 3-5 as a rule with 2-3 setae on each side, rarely proportion of setae 1+2. Microsculpture very faint, distinct only under magnification x50, consisting on head of very short transverse meshes, on pronotum meshes slightly longer, on elytra transverse meshes longer and wider than on pronotum. Aedeagus (Figs 90, 91) slender, with short narrow apex, right paramerae - Figs 98, 99. Length 8.6-11.1 mm. Width 3.3-4.5 mm. Material. Kuban district, northern slope of Fisht Mt.; Kuban district, source of Kurdzhiis