Identification:Thorax: Humeri amber, Mesonotum amber, sclerites above the coxae black (that above the fore coxa may be amber). Mesopleuron amber. Legs: In N. ephippium only the hind femur has two dark rings whereas in N. octoannulata both the mid and hind femora have dark rings. (Czerny, 1930) Abdomen: Distinctive sigmoidal shape. Males: The males are very distinctive, Collin describes the ventral lobes as "a tubular projection from each side of the fourth sternite, pointing towards the rear, and sharply bent towards each other at their tips, which are dilated into rounded knobs" Size: 4-5 mm
One of two species with a distinctly amber coloured thorax. In N. ephippium this colouration extends down the sides of the thorax whereas in N. octoannulata the amber is confined to the top (mesonotum). To date N. octoannulata has only been recorded on the Iberian peninsula (and Turkey) where there are no records of N. ephippium, the two are geographically isolated.