The short vein within the first submarginal cell (SCI) is variously described as vein lr or the ‘spur vein’. This vein is obvious in many Thynninae, including virtually all Thynnini. However, it is absent or barely indicated in Iswaroidini, another of the Thynninae tribes.

The relative positions of the ‘recurrent veins’, particularly 2m-cu, and the 2nd submarginal cell cross vein (2r-m) is particularly important in distinguishing the Thynninae tribes.

The subfamily Diamminae consists of a single species, Diamma bicolor. While the females are easily identified (large, metallic blue, often seen moving freely above ground), males are less distinctive. Their forewing venation, however, provides a very good clue. In Diamminae, 2m-cu meets SCII. In nearly all other Thynninae, 2m-cu meets SCIII.