Lema cyanella (L.) and Oulema obscura (Stephens)
Oulema obscura (Stephens) and Lema cyanella (Linnaeus) were at one stage both included in Lema. Although Joy keys out both species quite easily there is some confusion with the nomenclature. Lema puncticollis Curtis in Joy is the current Lema cyanella (Linnaeus) whereas Lema cyanella in Joy is the current Oulema obscura (Stephens). There are three main differential characters between the two species:
Pronotal contraction The contraction in each side of the pronotum in cyanella is normally in the middle or sometimes slightly towards the base whereas in obscura it is at the base. Both species have a, normally, obvious transverse furrow at the base and in obscura this will align with the lateral contractions in cyanella the contractions are further forward and do not align with the furrow. The pronotum anterior of the furrow in cyanella is somewhat depressed whereas in obscura the pronotum appears distended or 'swollen'.
Lema Cyanella	Oulema obscura
Lema Cyanella	Oulema obscura
Puncturation In obscura the pronotal puncturation is very sparse so much so that some specimens can appear almost impunctate. In cyanella the puncturation is obvious and much denser, very often with the punctures only the width of a puncture apart (see above). The elytral striae puncturation is also finer in cyanella than obscura
Lema Cyanella	Oulema obscura
Size O.obscura is a noticeably smaller species when the two are compared together. Joy gives 3-4mm for obscura and in cyanella 4-5mm. This is certainly the case for our specimens with obscura measuring between 3.2-3.7mm and cyanella 4.2-5mm.
Lema Cyanella	Oulema obscura
Lema Cyanella	Oulema obscura
Lema Cyanella
Oulema obscura
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