28.014 Crassa unitella (Brown Bark Moth)
ws: 13-17mm (MBGBI4.1), fw 6-8mm (Sterling & Parsons), 5.3-7.3mm (my specimens); Jun-Aug; fungus and dead bark on various trees; common in S.England and Wales, more local in N.England
Synonym: Batia unitella (MBGBI4.1)
Synonym: Batia unitella (MBGBI4.1)
Crassa unitella §1 female
Generic features: Head with appressed scales; Antenna 3/4 fw length; ciliate in male; scape with pecten; Labial palps long, slender; S2=S3
Fw V8&7 stalked, V2 arising from 4/5 length of cell; Hw V4&3 connate; Abdomen with patches of spiny scales dorsally
Male genitalia: vinculum >1/2 length of valva; pointed process at end of sacculus
ID: Very similar to Crassa tinctella, which flies May-Jun. C.unitella has a head down resting posture while C.tinctella has a horizontal posture. In C.unitella the head and palps are contrasting bright ochreous yellow vs much less contrasting ochreous orange in C.tinctella - though this difference may be less apparent with wear.
Male genitalia: In C.unitella the aedeagus has a strongly dentate sclerotisation near the apex of the tunica and a weak linear cornutus; in C.tinctella the tunica is not strongly sclerotised an lacks teeth and has a moderate linear cornutus.
Female genitalia: In C.unitella the introitus is funnel-shaped and the bursa lacks a signum; in C.tinctella the introitus is more strongly sclerotised and more cyclindrical and the bursa contains a moderate plaque-like signum
Fw V8&7 stalked, V2 arising from 4/5 length of cell; Hw V4&3 connate; Abdomen with patches of spiny scales dorsally
Male genitalia: vinculum >1/2 length of valva; pointed process at end of sacculus
ID: Very similar to Crassa tinctella, which flies May-Jun. C.unitella has a head down resting posture while C.tinctella has a horizontal posture. In C.unitella the head and palps are contrasting bright ochreous yellow vs much less contrasting ochreous orange in C.tinctella - though this difference may be less apparent with wear.
Male genitalia: In C.unitella the aedeagus has a strongly dentate sclerotisation near the apex of the tunica and a weak linear cornutus; in C.tinctella the tunica is not strongly sclerotised an lacks teeth and has a moderate linear cornutus.
Female genitalia: In C.unitella the introitus is funnel-shaped and the bursa lacks a signum; in C.tinctella the introitus is more strongly sclerotised and more cyclindrical and the bursa contains a moderate plaque-like signum
§1 Strumpshaw Fen, Norfolk; 23/07/2008; female; fw 7.2mm
§2 Strumpshaw Fen, Norfolk; 28/07/2012; male; fw 6.6mm
§3 Westcliff-on-sea, Essex; 15/07/2014; female; fw 6.8mm
§4 Arne, Dorset; 03/07/2016; female; fw 6.9mm; to light
§5 Foulness, Essex; 24/06/2017; female; fw 7.3mm; to light
§6 Westcliff-on-sea, Essex; 01/07/2019; female; fw 6.8mm; to light
§7 Pound Wood, Essex; 23/07/2019; male; fw 5.3mm; to light
§8 Westcliff-on-sea, Essex; 19/08/2021
All images © Chris Lewis
§2 Strumpshaw Fen, Norfolk; 28/07/2012; male; fw 6.6mm
§3 Westcliff-on-sea, Essex; 15/07/2014; female; fw 6.8mm
§4 Arne, Dorset; 03/07/2016; female; fw 6.9mm; to light
§5 Foulness, Essex; 24/06/2017; female; fw 7.3mm; to light
§6 Westcliff-on-sea, Essex; 01/07/2019; female; fw 6.8mm; to light
§7 Pound Wood, Essex; 23/07/2019; male; fw 5.3mm; to light
§8 Westcliff-on-sea, Essex; 19/08/2021
All images © Chris Lewis
Page published 09/11/2011 | §2 added 28/10/2012 | Genus changed from Batia 10/03/2014 | §3 added 31/01/2015 (female genitalia) |
§4 added and text revised 22/09/2016 | §5 added 22/10/2017 | §6 added 22/02/2020 | §7 added 01/03/2020 | §8 added 14/12/2021
§4 added and text revised 22/09/2016 | §5 added 22/10/2017 | §6 added 22/02/2020 | §7 added 01/03/2020 | §8 added 14/12/2021
