15.004 Caloptilia elongella (Alder Stilt)
ws: 14–16mm; bivoltine - Jun, Sep‐Apr; alder (Alnus glutinosa); common throughout UK.
Caloptilia elongella §1 male
ID: S2 of labial palps not tufted; forewing chestnut-brown without any distinct markings > C.rufipennella / C.betulicola / C.elongella. C.rufipennella can usually be excluded on size (ws 11-12mm). According to the key in MBGBI2 C.betulicola/elongella can be distinguished on the basis that in C.betulicola the hindleg trochanter is white, while in C.elongella it is concolorous with the forewing or yellowish. Genital examination is probably required for confident separation of these two and for exclusion of larger C.rufipennella.
Male genitalia: The aedeagus of C.rufipennella contains a single long strong cornutus within the part of the vesica inside the tunica. Both C.betulicola and C.elongella have a cluster of small cornuti in the vesica anterior to the tunica; in C.betulicola there are a few (~6) relatively strong cornuti, all longer than the width of the aedeagus; in C.elongella the cornuti are more numerous and all are fine and shorter than the width of the aedeagus.
Male genitalia: The aedeagus of C.rufipennella contains a single long strong cornutus within the part of the vesica inside the tunica. Both C.betulicola and C.elongella have a cluster of small cornuti in the vesica anterior to the tunica; in C.betulicola there are a few (~6) relatively strong cornuti, all longer than the width of the aedeagus; in C.elongella the cornuti are more numerous and all are fine and shorter than the width of the aedeagus.
Dissection
Male genitalia
Female genitalia
§1 Strumpshaw Fen, Norfolk; 05/11/2015; male; fw 8.2mm
§2 Struy, Inverness-shire; 01/05/2016; female; fw 8.4mm
§3 Struy, Inverness-shire; 01/05/2016; female; fw 7.5mm
All images © Chris Lewis
§2 Struy, Inverness-shire; 01/05/2016; female; fw 8.4mm
§3 Struy, Inverness-shire; 01/05/2016; female; fw 7.5mm
All images © Chris Lewis
Page published 15/11/2015 (§1) | §2-3 added 25/06/2016
