In a recent volume of Zootaxa a group of Spanish Orthoptera researchers has shed light on the cryptic taxon Oecanthus dulcisonans . They provide field characters to distinguish it from the common O. p ellucens .
The easiest feature is the song, but also the hind wings are longer and the sternum is more slender in O. dulcisonans . These new insights will help to establish the distribution in Southern Europe. The paper provides an important preparation advice. When pinning crickets avoid the pronotum, as the sternal area provides useful characters.
Source: Cordero, P.J., V. Llorente, P. Cordero & J. Ortego 2009. Recognizing taxonomic units in the field - The case of the crickets Oecanthus dulcisonans Gorochov 1993, and O. pellucens (Scopoli, 1763) (Orthoptera: Gryllidae): implications for their distribution and conservation in Southern Europe. Zootaxa 2284: 63-68.