Structure of the wing ventral scales of Coenonympha Huebner, [1819] with special reference to C. pamphilus (L., 1758) and its morphotype lyllus (Esper, 1805) (Lepidoptera: Nymphalidae)

The surface morphology of the ventral wing scales of four species of Coenonympha is described in order to identify the nature of the colour of the premarginal silvery stripe which characterizes the taxon C. pamphilus lyllus (Esper, 1805). The surface morphology of most scales is relatively simple, showing a single row of wide pores (fenestrae) between each pair of ribs. Two types of reflective scales were identified: those of the silvery stripe and those of the white spots of the wing ocellli. In both types of scales the reflective effect is likely to arise from a partial or complete occlusion of the fenestrae, which matches observations by other authors on nymphalids with reflective wing paths. However, this is probably combined with further different structural effects in the two kinds of scales. The frequency of the silvery line among members of Coenonympha suggests that this feature -diagnostic for the lyllus morphotype with respect to the 'typical' C. pamphilus- represents an ancestral feature for this group.Original Abstract: Se describe la morfologia de las escamas de la cara ventral de las alas de cuatro especies de Coenonympha, con el objeto de identificar la naturaleza del color de la linea premarginal brillante que caracteriza el taxon C. pamphilus lyllus (Esper, 1805). La superficie de la mayor parte de las escamas es relativamente simple, mostrando una unica fila de grandes poros (fenestras) entre cada dos costillas. Se han identificado dos tipos de escamas reflectantes: las de la linea de brillo metalico, y las del punto bianco de la pupila de los ocelos. En ambos tipos, el efecto que produce el color bianco parece consistir en el cerramiento total o parcial de las fenestras, lo que coincide con observaciones realizados por otros autores en otros ninfalidos con disenos reflectantes. La frecuencia de la linea plateada en especies del genero hace pensar que esta caracteristica, que diferencia el morfotipo lyllus de la forma tipica de C. pamphilus, en un rasgo ancestral del grupo.