See individual species page for variability within each species
(click on image) |
|
1) Size: B.adustella ws 13-19mm (MBGBI4.1), fw 6-9mm (Sterling & Parsons); B.lacticolella ws 13-22mm, fw 6-11mm. So specimens with fw >9.0mm should be B.lacticolella.
2) Ground colour of forewing - In the key in MBGBI4.1 described as brown or dark fuscous in adustella, ochreous to buff in lacticolella. But in the species text as cream to buff variably irrorate dark fuscous often intensely in adustella, cream to ochreous sometimes with fuscous irroration in lacticolella. It seems that individuals with very heavy fuscous irroration are more likely to be adustella.
3) Both species may show an oblique dorsal strigula at 1/3 (pale proximally, fuscous distally), but this is a constant feature in adustella and may be reduced or absent in lacticolella. So individuals in which the dorsal strigula is reduced or absent should be lacticolella.
4) Both species usually show a dark double discal dot at 2/3; lacticolella may show an additional two dark dots between 1/3 and 2/3 - so the presence of these additional dots should indicate lacticolella - however I think they are often present but somewhat obscured in B.adustella
5) The key in MBGBI4.1 suggests that the terminal dots may be absent in lacticolella, and when they are present they are faint and reddish brown; while in adustella these dots are well-defined. In the text these are described as a "series of terminal evenly spaced dark dots, sometimes extending into the cilia and giving a chequered appearance" in adustella; "sometimes ends of veins faintly marked darker and an equally faint line in terminal cilia" in lacticolella.
6) Labial palps are described in MBGBI4.1 as "fuscous, darker below" in adustella; and "cream" in lacticolella. I have found that specimens that appear to be lacticolella on other features may have some fuscous marks on the palps, particularly on the ventral aspect of segment 2.
7) Leg colour "fuscous banded buff" in adustella; "foreleg cream to fuscous, mid and hindlegs cream" in lacticolella. This should be a clear distinction but I have found that specimens appearing to be lacticolella often have fuscous markings on the dorsal aspect of the mid- and hindtarsi.
8) Abdomen - buff to fuscous with darker bands more noticeable in paler specimens in adustella; cream with discrete transverse stripes in lacticolella. So specimens with a fuscous abdomen should be adustella.
2) Ground colour of forewing - In the key in MBGBI4.1 described as brown or dark fuscous in adustella, ochreous to buff in lacticolella. But in the species text as cream to buff variably irrorate dark fuscous often intensely in adustella, cream to ochreous sometimes with fuscous irroration in lacticolella. It seems that individuals with very heavy fuscous irroration are more likely to be adustella.
3) Both species may show an oblique dorsal strigula at 1/3 (pale proximally, fuscous distally), but this is a constant feature in adustella and may be reduced or absent in lacticolella. So individuals in which the dorsal strigula is reduced or absent should be lacticolella.
4) Both species usually show a dark double discal dot at 2/3; lacticolella may show an additional two dark dots between 1/3 and 2/3 - so the presence of these additional dots should indicate lacticolella - however I think they are often present but somewhat obscured in B.adustella
5) The key in MBGBI4.1 suggests that the terminal dots may be absent in lacticolella, and when they are present they are faint and reddish brown; while in adustella these dots are well-defined. In the text these are described as a "series of terminal evenly spaced dark dots, sometimes extending into the cilia and giving a chequered appearance" in adustella; "sometimes ends of veins faintly marked darker and an equally faint line in terminal cilia" in lacticolella.
6) Labial palps are described in MBGBI4.1 as "fuscous, darker below" in adustella; and "cream" in lacticolella. I have found that specimens that appear to be lacticolella on other features may have some fuscous marks on the palps, particularly on the ventral aspect of segment 2.
7) Leg colour "fuscous banded buff" in adustella; "foreleg cream to fuscous, mid and hindlegs cream" in lacticolella. This should be a clear distinction but I have found that specimens appearing to be lacticolella often have fuscous markings on the dorsal aspect of the mid- and hindtarsi.
8) Abdomen - buff to fuscous with darker bands more noticeable in paler specimens in adustella; cream with discrete transverse stripes in lacticolella. So specimens with a fuscous abdomen should be adustella.
Male genitalia: As far as I can see the only reliable difference is in the shape of the uncus:
broadest at base and tapers towards apex in B.lacticolella; broadest subapically, giving a clubbed appearance in B.adustella.
broadest at base and tapers towards apex in B.lacticolella; broadest subapically, giving a clubbed appearance in B.adustella.
|
|
Female genitalia: the main difference illustrated in MBGBI4.1 (p198) is in the length of the apophyses posteriores. In B.adustella the apophyses posteriores are ~2x as long as the apophyses anteriores; in B.lacticolella this ratio is ~2.5. In the examples shown here the ratios are 2.18 and 3.04 repsectively. In another specimen on the B.lacticolella page the ratio is 2.69. In the images shown at Moth Dissection the ratios are 2.16 and 2.6 respectively. So as a working proposition: in B.adustella the PP:AP ratio is 2.0 to 2.2 while in B.lacticolella it is >2.5.
|
|
Blastobasis phycidella
Separated in the key in MBGBI4.1 (p197) on basis of grey forewing ground colour and transverse (rather than oblique) dorsal strigula (when present). Moth Dissection indicates an appendage at the base of the antenna (probably arising from the apex of the scape). The male genitalia appear very similar to B.lacticolella, with a clubbed uncus; Moth Dissection also indicates a small linear sclerotisation at the apex of the aedeagus in addition to the long linear sclerotisation shown by all Blastobasis species. Female genitalia are illustrated in MBGBI4.1 (p198) and show extremely long posterior apophyses with a PP:AP ratio of 3.3 and a very long narrow ductus bursae without any significant sclerotisation; and possibly the signum has a straighter thorn.
Separated in the key in MBGBI4.1 (p197) on basis of grey forewing ground colour and transverse (rather than oblique) dorsal strigula (when present). Moth Dissection indicates an appendage at the base of the antenna (probably arising from the apex of the scape). The male genitalia appear very similar to B.lacticolella, with a clubbed uncus; Moth Dissection also indicates a small linear sclerotisation at the apex of the aedeagus in addition to the long linear sclerotisation shown by all Blastobasis species. Female genitalia are illustrated in MBGBI4.1 (p198) and show extremely long posterior apophyses with a PP:AP ratio of 3.3 and a very long narrow ductus bursae without any significant sclerotisation; and possibly the signum has a straighter thorn.
Page published 08/04/2016
