Key to the species of Decimiana (males only)

The key presented in Ippolito and Lombardo (2004) emphasized external characters that we observed to be highly variable within and among species, thus making species identification problematic. For instance, the size and shape of the pronotum, and the degree of excavation on the costal margin of the mesothoracic wings, show differences in conspecific populations that overlap with interspecific variation. As more species are described and new populations are characterized, it is possible that characters formerly considered as well delimited were artefacts of the small number of individuals that are usually available in collections for research at any given time. Male genital structures do provide with more consistent characters for species identification, and thus we devised a new key to species based on this structure in order to complement the one presented by Ippolito and Lombardo (2004).

1 Anterior process of the ventral lamina of the Ldp very sclerotized. Membranous lobe of the Ldp prominent, covered with long and thin setae (Fig. 2 A–D)..............................................................................2

- Anterior process of the ventral lamina of the Ldp prominent, globose to elongated and less sclerotized. Membranous lobe of the Ldp reduced, with granulations or setae (Fig.1E; 2E–L)....................................................3

2 Anterior process of the ventral lamina of the Ldp short, robust and bludgeon-like, bearing robust spines (Fig. 2 A–B). Vph with a semicircular outline; proximal process basally roundly produced, bearing denticles, narrowing to a point distally; distal process thin, sinuous, with denticles only on its base (Fig. 3 A)............................................. D. clavata

- Anterior process of the ventral lamina of the Ldp elliptical, bearing robust spines on its surface (Fig. 2 C–D). Vph subtriangular; proximal process wider in the base than in the apex but not particularly produced, with granulations and denticles; distal process curved, with denticles on the right edge (Fig. 3 B).............................................. D. elliptica

3 Anterior process of the ventral lamina of the Ldp robust, with setae or granulation along the entire length (Fig. 2 G–L)...... 4

- Anterior process of the ventral lamina of the Ldp slightly rounded, with spines or teeth well marked and differing in size, in some cases may be similar to a warbonnet (Fig. 1E; 2E–F).....................................................6

4 Anterior process of the ventral lamina of the Ldp with setae; membranous lobe rounded, covered by setae, similar to a wart (Fig 2 I–J; K–L); Vph subretangular and broad (Fig. 3 E–F)....................................................5

- Anterior process of the ventral lamina of the Ldp with small granulations; membranous lobe little pronounced, with some setae (Fig. 2 G–H); Vph subquadrangular small (Fig. 3 D)..................................................... D. rehni

5 Anterior process of the ventral lamina of the Ldp densely covered by setae; membranous lobe wart-like and covered by many setae (Fig. 2 K–L). Vph subrectangular; proximal process pointed, with denticles only in the right edge; distal process robust, without denticles; sinuous externally border (Fig. 3 F)................................................. D. bolivari

- Anterior process of the ventral lamina of the Ldp with small setae along the entire length, denser distally; membranous lobe

short, with setae (Fig. 2 I–J). Vph broad; proximal process thin, almost the same width in the base and in the apex, edge with denticles; distal process thin, with some granulations mainly apically, right edge with denticles (Fig. 3 E)........ D. hebardi 6 Anterior process of the ventral lamina of the Ldp warbonnet-like, globose, with sclerotized spines, some of them pointed and varying in size, distal portion with spines in the edge; membranous lobe with setae (Fig. 2 E–F). Proximal process of the Vph thin, short, with few striae marginally, almost the same width on the base and in the apex (Fig. 3 C)............ D. tessellata

- Anterior process of the ventral lamina of the Ldp globose, with irregular spines (teeth) not pointed, distal portion with few spines on the edge; membranous lobe slightly pronounced, granulated with very few tiny setae (Fig. 1E). Proximal process of the Vph robust, subtriangular, with scales on its surface, conical (Fig. 1D).................................. D. gaucha