Key to males and females of Sonesimia

1. Body, in dorsal view, elongate with sides approximately parallel; aedeagus, in lateral view, with pair of slender ventral processes............................................................................................... 2

- Body, in dorsal view, short and elliptical; aedeagus, in lateral view, with broad basiventral process...................... 4

2. Dorsum anteriorly with pair of black to brown stripes extending from apex of crown to pronotum; frons with wide black to brown area on median portion; male pygofer with pair of dorsal processes flattened dorsoventrally, truncate in ventral view; apical portion of aedeagal processes, in lateral view, overlapping or very close to shaft; female sternite VII with pair of long posterolateral processes and short median rounded lobe....................................................... 3

- Dorsum anteriorly with pairs of small black to brown maculae on crown and anterior portion of pronotum; frons widely yellow, without black to brown area on median portion; male pygofer with pair of short, dorsal spiniform processes; apical portion of aedeagal processes, in lateral view, remote from shaft; female sternite VII with pair of short posterolateral processes, without median lobe....................................................... S. dimidiata (southern Brazil, Argentina)

3. Pronotum with pair of longitudinal median stripes attaining posterior margin and connected to each other medially, and pair of posterolateral subtriangular maculae, black to brown; male pygofer with pair of long dorsal processes; subgenital plates, in ventral view, subtriangular; aedeagal shaft, in lateral view, long and narrow with apex abruptly broadened; female sternite VII with pair of posterolateral processes acute and medially turned................. S. grandis (southeastern Brazil, Paraguay)

- Pronotum with pair of longitudinal median stripes not attaining posterior margin nor connected to each other medially, and without pair of posterolateral maculae, black to brown; male pygofer with pair of very short dorsal processes; subgenital plates, in ventral view, semicircular; aedeagal shaft, in lateral view, short and gradually broadened distally; female sternite VII with pair of posterolateral processes narrowly rounded and posteriorly directed................. S. chinai (southern Brazil)

4. Dorsum anteriorly with pair of broad stripes continuous at least on crown, black to brown............................ 5

- Dorsum anteriorly with pair of narrow stripes variably interrupted, sometimes forming pairs of approximately aligned maculae, black to brown................................................................................... 6

5. Dorsum with pair of black to brown stripes not attaining posterior margin of pronotum; male pygofer, in lateral view, broadly convex apically, without processes; aedeagus with basiventral process distinctly longer than shaft, rectilinear with apical portion curved anteriorly; female sternite VII with two pairs of short rounded processes, one lateral and one posterolateral............................................... S. grossa (southeastern and southern Brazil, Argentina, Bolivia, Paraguay)

- Dorsum with pair of black to brown stripes attaining posterior margin of pronotum; male pygofer, in lateral view, narrowly convex apically, with dorsal pair of subapical inner unciform processes; aedeagus with basiventral process approximately as long as shaft, strongly curved anteriorly; female sternite VII with pair of short posterolateral narrowly rounded processes......................................................... S. rafaeli (central-western, southeastern, and southern Brazil)

6. Male pygofer, in lateral view, broadly convex apically, with dorsal, subapical minute spiniform process; aedeagus with basiventral process distinctly longer than shaft; aedeagal shaft long and narrow, without dorsal subapical lobe; female sternite VII with pair of long posterolateral acute processes and median lobe slightly emarginated....... S. cleusae (southern Brazil)

- Male pygofer, in lateral view, narrowly convex apically, with dorsal subapical inner unciform process; aedeagus with basiventral process approximately as long as shaft; aedeagal shaft short and broad, with dorsal subapical lobe; female sternite VII with pair of short posterolateral narrowly rounded processes and median broad concavity........ S. nessimiani, sp. nov. (Bolivia)