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Insects of Britain and Ireland |
Wing venation is best viewed from the under-side, where it is more prominent but may still require removal of the scales.
The neuration characters and data were taken primarily from Meyrick (1927). Unsurprisingly (see below), cross-referencing the resulting descriptions in detail with Imms (1957), Le Cerf and Herbulot (1948), and Common (1970) has resulted in considerably increasing the levels of intra-taxon variation encoded.
The abstruse descriptive terminologies for lepidopteran venation employed in modern entomological textbooks represent attempts to standardise across all the insect groups, and involve entangling the descriptive process with phylogenetic hypotheses of doubtful validity. The simpler system presented by Meyrick (1927), which is easier to apply to a specimen in practice, is used here. He provides a wealth of comparative data and drawings of neuration for British Lepidoptera, presumably reflecting his own efforts at consistent interpretation. However, the requirement to identify veins with his standard numbering still involves recognising veins that are ‘missing’ with reference to the ‘standard’ (see diagram). Also, in the absence of precise definitions, there are evident difficulties in making the required distinctions between ‘tubular’ veins and their vestigial (‘reduced’, ‘obsolescent’, ‘obsolete’, etc.) manifestations. Contrasting interpretations by different authorities of neuration patterns for the same species are common (see our accounts of Endromis versicolora and Sesia bombiformis). The available data are evidently untrustworthy, and since neuration characters are inconvenient for application, their frequent use at critical positions in professional printed keys is unfortunate.