This is based on a translation of Taeger (1989), augmented with data gained from examination of specimens which have only recently become available. Body length: female 8.0 mm, male 6.5 mm. Female (Fig. 119) and male (Fig. 120) are similar in colour, apart from the mesopleura: upper mesepisternum pale in female, entirely dark in male. Head and antenna black, except for pale palps and labrum. Thorax dorsally black, with pale tegula and more or less pronotum. Legs entirely pale except more or less for tarsomeres. Wing venation entirely pale brown. Abdomen yellow except more or less for tergum 1. Antennomere 3 little shorter than 4. Postocellar field ca. twice as wide as long; ocellus diameter : POL : OOL = 1 : 1.7 : 2.0; frontal field enclosed by indistinct bulges; supra-antennal groove indistinct; head weakly punctured and shiny; frontal field partly finely wrinkled; thorax slightly more strongly punctured than head. Mesepisternum shiny, with indistinct punctures, evenly covered with rather dense, pale pubescence. Legs relatively thick: femora 3.5 times as long as wide, 0.66 times as long as the tibia; tibia 6.5 times as long as wide and 1.2 times as long as the metatarsus; inner spur of the metatibia nearly as long as the apical width of tibia.

Female: upper half of mesepisternum pale, lower half black. Pronotum, mesepimeron, and metapleura entirely pale. Propleuron edged with black. Head behind eyes subparallel. Antennomere 8 approx. three times as long as wide. Lancet: Fig. 121.

Male: mesepisternum completely black. Pronotum ventrally black. Mesepimeron and metapleura partly pale. Propleuron completely black. Anterior of abdominal tergum 2 also black. Fore wing length 6.5 mm; antennomere 8 3.5 times as long as wide; head behind the eyes clearly narrowed; tergite 8 without special structures; subgenital plate apically rounded. Penis valve: Fig. 122.

In the West Palaearctic, Mesoneura opaca and lanigera are superficially similar in habitus to Neodineura arquata.

Unknown.

Only known from Germany, Switzerland (Taeger et al. 2006), the Czech Republic (Beneš and Holuša 2015), and the Russian Caucasus (see below). We are only aware of the existence of four extant collection specimens: three females and one male. Taeger (1989) interpreted the handwritten label data on the only known male (SDEI) as “Sandbg. [Sandberg] 11.V.91”, and thought it likely that the locality was one of several of that name within the then German-speaking territories. Alternatively, it could refer to “Sonderburg” [German name for the Danish island Sønderborg], although the second letter on the label does look more like an “a” than an “o”. Konow received many sawfly specimens, some still in the Konow Collection at the SDEI, from W. Wüstnei, who resided at Sonderburg, and collected from around the late 1880’s to the early 1900’s.

No records.

(to the best of our knowledge, the following are the only known extant collection specimens of this species):

Czech Republic [not examined: data from Beneš and Holuša 2015]: Moravia: 1♀, Stolařka Mt., Lhotka, 700 m, 21.05.1998, leg. J. Holuša (NMPC). Germany, or Denmark?: 1♂ (DEI-GISHym54879 / pr.239.(AZ), examined), “Sandbg.” or “Sondbg.”, 11.05.1891 (SDEI). Russia: 1♀ (DEI-GISHym15240, examined), Teberda Reserve, Alibek, 2000 m, 43.32000N, 41.51000E, 22.06.1972, leg. V. Ermolenko (HNHM). Switzerland: 1♀ (DEI-GISHym19777, examined), Solothurn, Rickenbach, 47.34987N, 7.85025E, 560 m, 24.04.1994, leg. Flückiger (SDEI).