49.195 Bactra furfurana (Marsh Lance)
ws: 13-19mm; Jun-Jul; common club-rush (Schoenoplectus lacustris), bog rush (Juncus subuliflorus); local in marshes, riverbanks throughout GB
Bactra furfurana §1 male
ID: Varies somewhat in: colour of markings from brown-ochreous to brown-ferruginous; extent of black in the markings; suffusion of the ground colour with grey; strength of the markings. Usually identifiable from the reticulate markings overlaying the areas of ground colour and the usually well-developed median fascia. Weakly marked individuals need genital dissection to identify.
Male genitalia: In B.furfurana and B.lacteana the spines of the sacculus do not cross its edge; in both B.lancealana and B.robustana the saccular spines clearly protrude from its edge. In B.furfurana there are 5-9 spines, in B.lacteana there are 2-4 spines. In B.furfurana there are relatively few spines at the sacculo-valvar junction compared with B.lacteana.
Female genitalia: Ostium small, anterior lip simple, posterior lip a narrow band extending only a little beyond the ostium laterally
Male genitalia: In B.furfurana and B.lacteana the spines of the sacculus do not cross its edge; in both B.lancealana and B.robustana the saccular spines clearly protrude from its edge. In B.furfurana there are 5-9 spines, in B.lacteana there are 2-4 spines. In B.furfurana there are relatively few spines at the sacculo-valvar junction compared with B.lacteana.
Female genitalia: Ostium small, anterior lip simple, posterior lip a narrow band extending only a little beyond the ostium laterally
The 5-9 spines of the sacculus do not cross its edge; there are few spines at the sacculo-valvar junction
§1 Strumpshaw Fen, Norfolk; 23/08/2012; male; fw 6.7mm
§2 Foulness, Essex; 13/08/2016; male; fw 7.6mm
§3 Foulness, Essex; 13/08/2016; female; fw 8.1mm
§4 North Warren, Suffolk; 16/07/2017
§5 North Warren, Suffolk; 16/07/2017
§6 Dungeness, Kent; 10/06/2019; male; fw 6.9mm
§7 Westcliff-on-sea, Essex; 10/08/2023; male; fw 8.4mm
All images © Chris Lewis
§2 Foulness, Essex; 13/08/2016; male; fw 7.6mm
§3 Foulness, Essex; 13/08/2016; female; fw 8.1mm
§4 North Warren, Suffolk; 16/07/2017
§5 North Warren, Suffolk; 16/07/2017
§6 Dungeness, Kent; 10/06/2019; male; fw 6.9mm
§7 Westcliff-on-sea, Essex; 10/08/2023; male; fw 8.4mm
All images © Chris Lewis
Page published 09/01/2013 (§1) | §2&3 added 07/05/2017 | §4&5 added 05/04/2018 | §6 added 13/02/2020 | §7 added 21/12/2023
