Key to Stigmella species |
Group C.
Species with a plain forewing
S. tiliae anomalella spinosissimae viscerella paradoxa magdalenae nylandriella oxyacanthella pyri minisculella desperatella zelleriella incognitella perpygmaeella suberivora svenssoni ruficapitella atricapitella samiatella roborella
Species with a plain forewing
S. tiliae anomalella spinosissimae viscerella paradoxa magdalenae nylandriella oxyacanthella pyri minisculella desperatella zelleriella incognitella perpygmaeella suberivora svenssoni ruficapitella atricapitella samiatella roborella
C1: Terminal cilia contrastingly pale > S.zelleriella
This is the only species with a plain forewing with distinctly contrastingly pale terminal cilia*. Head colour is somewhat variable and shows sexual dimorphism: ♂ grey-brown ♀ yellowish-white to ochreous or orange; collar yellowish white. The forewing varies from fairly plain and dark to showing a strong contrast between shining pale grey-brown proximally dark brown to purplish distally. It may have an ill-defined fascia (and is also keyed in Group B). ♂antenna ⅗ forewing length.
*S.tiliae has a purple forewing apex and grey cilia which gives a degree of contrast.
This is the only species with a plain forewing with distinctly contrastingly pale terminal cilia*. Head colour is somewhat variable and shows sexual dimorphism: ♂ grey-brown ♀ yellowish-white to ochreous or orange; collar yellowish white. The forewing varies from fairly plain and dark to showing a strong contrast between shining pale grey-brown proximally dark brown to purplish distally. It may have an ill-defined fascia (and is also keyed in Group B). ♂antenna ⅗ forewing length.
*S.tiliae has a purple forewing apex and grey cilia which gives a degree of contrast.
C2: Head black or blackish
C2: a) Collar dark > ♂S.ruficapitella, ♂S.atricapitella
- Androconial scales in basal half of hindwing extending to ⅓ length of cilia > S.ruficapitella
- Androconial scales along most of hindwing fringe extending to ⅔ length of cilia > S.atricapitella
C2: b) Collar pale > S.tiliae, S.anomalella, S.spinosissimae, S.viscerella, S.minusculella, S.samiatella, ♀S.atricapitella
- Distinct colour contrast between greenish-bronze forewing base and purplish-brown apex > S.anomalella. All other species in this group are essentially unicolorous, though often just a shade darker at the apex. ♂S.anomalella shows a patch of darker scales at the hindwing base.
- S.samiatella and ♀S.atricapitella may have a reddish frons contrasting with the black vertex, but this is not reliably diagnostic
- The rest of this group requires Gen.det
C3: Head red or reddish
C3: a) Collar dark > S.desperatella, ♂S.suberivora
- Androconial scales in hindwing > S.suberivora. These are extensive: dorsal to ¾ cilia length, costal spatulate to > cilia length
- S.desperatella is extinct in GB
C3: b) Collar pale
C3: b) 1: Distinct colour contrast between forewing base and apex > S.anomalella, S.pyri
- Greenish-bronze forewing base, purplish-brown apex > S.anomolella. ♂S.anomalella show a patch of darker scales at the hindwing base.
- Golden-brown forewing base, apical ⅓ abruptly purple > S.pyri. ♂S.pyri has short dorsal androconial scales.
- All other species in C3b are essentially unicolorous, though often just a shade darker at the apex. S.oxyacanthella may show a more extensive purple suffusion at the apex but this probably not sufficient to amount to a distinct colour contrast
C3: b) 2: Hindwing features > ♂S.suberivora, ♂S.roborella, ♂S.svenssoni
- Androconial scales extensive: dorsal to ¾ cilia length, costal spatulate to > cilia length > S.suberivora
- Androconial scales indistinct: a cover of pale brown scales > S.roborella
- Basal half with thin scale cover, the scales arranged in a fish-bone pattern with a central row of small oblique scales > S.svenssoni
C3: b) 3: Not identifiable on external features > S.viscerella, S.paradoxa, (S.magdalenae), S.nylandriella, S.oxyacanthella, S.minisculella, S.incognitella, S.perpygmaeella, ♀S.svenssoni, ♀S.ruficapitella, ♀S.roborella
- Some segregation of males is probably achievable on antennal length: for most species this is ~½ forewing length, but in S.paradoxa, S.incognitella, and S.perpygmaeella it is ⅗ forewing length
- The antenna of ♀S.viscerella is especially short being markedly <½ forewing length
- ♀ S.incognitella and S.perpygmaeella have long grey anal tufts - the presence of this feature may indicate one of these two.