12.016 Nemapogon cloacella (Cork Moth) 0216
ws:10-18mm; May-Sep; fly in early morning sun & late afternoon to dusk, common throughout UK especially in woodland.
ID: According to MBGBI2, N.cloacella has an anvil-shaped dark mark on the costa at 1/2. In N.wolffiella the ground colour is more uniformly dark so that this dark costal mark is not clearly defined. On this basis I was expecting specimen §5 to be N.wolffiella - however, it has proved on genital dissection to be N.cloacella - suggesting to me that these species may not be reliably separable on external characteristics.
Male genitalia: N.cloacella and N.wolffiella, and other Nemapogon species are figured in MBGBI2 and there are images at dissection group. I will only consider N.cloacella vs N.wolffiella here. In MBGBI2 they are said to be distinguished by "the shape of the gnathos arms" - other than that no description is offered. I propose 4 consistent differences on the basis of the figures and images and my own N.cloacella material:
A: The gnathos arm is angular with a lateral section in the long axis of the genitalia and a transverse medial section. In N.cloacella there is a distinct projection at the "elbow" where these two components meet; the medial section is slightly shorter than the lateral section; and the medial section shows a distinct kink posteriorly towards the apex. In N.wolffiella there is no projection at the "elbow"; the medial section is distinctly longer than the lateral section; and the medial section is smoothly curved towards the apex.
B: Folds at the lateral margins of the tegumen are much "fuller" in N.cloacella.
C: In N.cloacella the apex of the sacculus is obliquely truncate with the lateral margin extending further than the medial margin. In N.wolffiella the sacculus is evenly rounded.
D: In N.cloacella the juxta has a medial notch, while in N.wolffiella it is evenly domed.
There are probably also differences in the aedeagus, but the preparations at dissection group are damaged and the drawings in MBGBI2 are not fully consistent with the images I have obtained for N.cloacella.
Page published Feb 2011 | Specimen §4 added 19/12/2011 | specimen §5 and ID section added 26/06/2012