Key to Elachistidae |
In my experience so far few Elachistidae can be identified with confidence on external features:
Elachista argentella is the only all white Elachistid
Elachista subalbidella could be confused with E.argentella but it is pale yellowish-buff rather than pure white
Elachista rufocinerea is the only Elachistid with a reddish-ochreous suffusion of the forewing and it has a distinctive reddish median thoracic line
Elachista triatomea and E.biatomella both have whitish forewings with two linear midwing black spots and a sometimes obscure tornal black spot - E.triatomea has a plain white ground colour while in E.biatomella the forewing is suffused brownish-fuscous to a variable extent.
E.maculicerusella can usually be identified from its pattern of forewing spots
Well-marked specimens of species in Group E (see below and key to group E) may be identifiable on external features when experience is gained.
All other species I would confirm by genital dissection - this is not easy as the genitalia of both sexes are tiny and the small differences between the species are difficult to be sure of.
Elachista argentella is the only all white Elachistid
Elachista subalbidella could be confused with E.argentella but it is pale yellowish-buff rather than pure white
Elachista rufocinerea is the only Elachistid with a reddish-ochreous suffusion of the forewing and it has a distinctive reddish median thoracic line
Elachista triatomea and E.biatomella both have whitish forewings with two linear midwing black spots and a sometimes obscure tornal black spot - E.triatomea has a plain white ground colour while in E.biatomella the forewing is suffused brownish-fuscous to a variable extent.
E.maculicerusella can usually be identified from its pattern of forewing spots
Well-marked specimens of species in Group E (see below and key to group E) may be identifiable on external features when experience is gained.
All other species I would confirm by genital dissection - this is not easy as the genitalia of both sexes are tiny and the small differences between the species are difficult to be sure of.
Key - based on male genitalia (MBGBI3)
Uncus lobes |
Valva |
Gnathos |
|
absent / much reduced |
narrows to an apical point |
Perittia obscurepunctella |
|
absent |
distinct apical cucullus |
Elachista gleichenella |
|
claw-like |
Elachista stabilella/freyerella/consortella (formerly Cosmiotes) |
||
pointed |
pointed pre-apical dorsal projection |
Stephensia brunnichella |
|
rounded |
paired |
Elachista trapeziella /cinereopunctella /serricornis /scirpi /eleochariella /utonella /albidella (formerly Biselachista) |
|
rounded |
simple |
all other Elachista |
Key to species based on forewing colour and markings:
Group A |
unicolorous |
Elachista argentella/festucicolella/subalbidella/rufocinerea/canapennella/orstadii Perittia obscurepunctella |
pale with darker markings |
Elachista cahorsensis/triseriatella/maculicerusella/triatomea/collitella/subocellea |
|
Group C* |
markings both paler and darker than the ground colour |
Elachista biatomella/serricornis/utonella/scirpi/eleochariella/albidella |
Group D |
dark with a single pale transverse fascia at 1/2 |
Elachista adscitella/obliquella/gangabella/bisulcella/unifasciella/cingilella |
dark with pale markings involving bases of terminal or apical cilia |
Elachista stabilella/freyerella/consortella/trapeziella/cinereopunctella |
|
dark with pale costal and tornal spots and no other pale markings* |
Elachista alpinella/humilis/subnigrella/canapennella/orstadii/serricornis |
|
dark with pale costal and tornal spots and other pale markings |
Elachista apicipunctella/gleichenella/regificella/geminatella/tengstromi/ albifrontella/nobilella/luticomella/alpinella/eskoi/bedellella/kilmunella/littoricola/ atricomella/poae/pomerana/canapennella/orstadii/subnigrella/humilis Stephensia brunnichella |
*Some specimens of species in Group E (especially E.consortella, in my experience) may be pale enough that otherwise obscured dark markings become apparent such that they key in Group C - look for the pale mark at the apex.
*Group F is males only - the corresponding females occur in Group G except for E.serricornis which is in Group C
*Group F is males only - the corresponding females occur in Group G except for E.serricornis which is in Group C
I have, so far, constructed keys to males of Groups B, E, F and G - follow the links above
Initially published on the Elachistidae page March 2011 | Key to Group G amended 29/12/2011 | Key to Groups F&G amended 20/03/2014 | Amended to replace genera Cosmiotes and Biselachista with Elachista and key to Groups F&G further amended 26/04/2014
