Subfamily: Dichomeridinae
Dichomeris (4S)
Ocelli present
Antenna with apical 2/3 serrate, ciliate in male (except D.alacella); scape without pecten
Labial palp S3 >= S2 (< in D.alacella); S2 with large ventral brush of scales (except D.alacella where thickened with appressed scales)
Fw elongate; V7&8 stalked, V7 to costa (except D.alacella where V7 absent V8&9 stalked)
Hw broader than fw (= in D.alacella); trapezoidal/subtrapezoidal; apex hardly produced (pointed in D.alacella); termen slightly sinuate; tornus rounded; V7&6 connate or stalked, V4&3 connate
Male genitalia: posterior margin of vinculum with enlarged assymetrical lobes or if not then aedeagus with long cornutus (>1/2 length of aedeagus)
Ocelli present
Antenna with apical 2/3 serrate, ciliate in male (except D.alacella); scape without pecten
Labial palp S3 >= S2 (< in D.alacella); S2 with large ventral brush of scales (except D.alacella where thickened with appressed scales)
Fw elongate; V7&8 stalked, V7 to costa (except D.alacella where V7 absent V8&9 stalked)
Hw broader than fw (= in D.alacella); trapezoidal/subtrapezoidal; apex hardly produced (pointed in D.alacella); termen slightly sinuate; tornus rounded; V7&6 connate or stalked, V4&3 connate
Male genitalia: posterior margin of vinculum with enlarged assymetrical lobes or if not then aedeagus with long cornutus (>1/2 length of aedeagus)
Acompsia (2S)
Brachmia (2S)
Head thickly clothed with scales covering frons
Antenna 4/5 length of fw
Labial palp long, curved, ascending; S2 thickened with appressed scales; S2 <= S3
Forewing termen sinuate; V2&3 stalked; V7&8 stalked, V7 to apex
Hw = breadth to fw; trapezoidal, termen sinuate; cilia as long as breadth of wing; V3&4 connate or stalked, V6&7 stalked
Male genitalia: Uncus pointed
Head thickly clothed with scales covering frons
Antenna 4/5 length of fw
Labial palp long, curved, ascending; S2 thickened with appressed scales; S2 <= S3
Forewing termen sinuate; V2&3 stalked; V7&8 stalked, V7 to apex
Hw = breadth to fw; trapezoidal, termen sinuate; cilia as long as breadth of wing; V3&4 connate or stalked, V6&7 stalked
Male genitalia: Uncus pointed
The two British Brachmia species are readily separable by the presence of dark fasciae in B.blandella and their absence in B.inornatella
Helcystogramma (3S)
Head thickly clothed with scales covering frons
Antenna 4/5 length of fw, shortly ciliate in male
Labial palp long, curved, ascending; S2 thickened with appressed scales; S2<=S3
Forewing termen straight or hardly sinuate; V2&3 stalked, V7&8 stalked, V7 to apex, V9 out of or connate with V7
Hw = breadth with fw; trapezoidal, termen sinuate; cilia as long as breadth of wing; V3&4 connate or stalked, V6&7 stalked
Male genitalia: aedeagus with small apical hook
Head thickly clothed with scales covering frons
Antenna 4/5 length of fw, shortly ciliate in male
Labial palp long, curved, ascending; S2 thickened with appressed scales; S2<=S3
Forewing termen straight or hardly sinuate; V2&3 stalked, V7&8 stalked, V7 to apex, V9 out of or connate with V7
Hw = breadth with fw; trapezoidal, termen sinuate; cilia as long as breadth of wing; V3&4 connate or stalked, V6&7 stalked
Male genitalia: aedeagus with small apical hook
H.triannulella is quite distinct. The other two British Helcystogramma species may be distinguished by the presence of brown scales on the lateral sides of the labial palps in H.rufescens and their absence in H.lutatella. The latter is rare and only found on the Dorset coast between Portland and Kimmeridge.