Key to species (14) of S. gestroi group
1. Elytra more slender with ratio: EL/EW 1.81–1.90. (Calabria, excluded S. gestroi).................................. 2
1’ Elytra less slender with ratio: EL/EW 1.75–1.80. (Campania). (Figs. 26–26e)......................... S. sbordonii sp.n.
2. Pronotum longer than wide (PL/PW 1.10–1.20)............................................................. 3
2’ Pronotum as long as wide or slightly elongate (PL/PW 1.00–1.10)............................................... 4
3. Elytral setae elongate. Elytral striae with punctures wide and deep. Rostrum ratio: RL/RW 1.50–1.75. (Figs. 24–24e).............................................................................................. S. obsoleta sp.n.
3’ Elytral setae not elongate. Elytral striae with punctures not wide and not deep. Rostrum ratio: RL/RW 1.25–1.35. (Figs. 22– 22e)................................................................................ S. cajetanibelloi sp.n.
4 Rostrum slender (RL/RW 1.55–1.67). First article of funicle long. (Figs. 29–29e).......................... S. zoiai sp.n.
4’ Rostrum more robust (RL/RW 1.17–1.50). First article of funicle short........................................... 5
5 Rostrum short (RL/RW 1.17–1.20). Maximum width pronotum in distal part (Figs. 27–27e)............. S. tedeschii sp.n.
5’ Rostrum elongate (RL/RW 1.29–1.50). Maximum width pronotum at middle...................................... 6
6. Elytra sub-parallel to sides and subflat on disc.............................................................. 7
6’ Elytra sub-oval to sides and vaulted on disc............................................................... 10
7. Pronotum sinuate to sides. Elytral setae short and recumbent. (Figs. 19–19e)............................ S. calida sp.n.
7’ Pronotum rounded to sides. Elytral setae long and raised or semierect............................................ 8
8. Pronotum punctures shallow. Elytral declivity strong> 60 degrees. (Figs. 20–20e).......................... diottii sp.n.
8’ Pronotum punctures evident. Elytral declivity moderate <60 degrees............................................. 9
9. Pronotum elongate (PL/PW 1.07–1.09). Eyes visible, convex. (Figs. 28–28e).......................... S. venusta sp.n.
9’ Pronotum as long as wide (PL/PW 1.00–1.00). Eyes just visible, flat. (Figs. 17–17e)............. S. fraterna Baviera, 2015
10. Pronotum elongate (PL/PW 1.08–1.10). Carinae on rostrum sub-parallel to sides. (Figs. 25–25e)........... S. poggii sp.n.
10’ Pronotum as long as wide (PL/PW 1.00–1.03). Rostral carinae of divergent to sides................................ 11
11. Legs thin and elongate. Elytral punctures very spaced and small. (Figs. 21–21e)........................ S. fancelloi sp.n.
11’ Legs short and robust. Elytral punctures more or less spaced and wide.......................................... 12
12. Elytra more rounded to side. Rostrum less slender (RL/RW 1.40–1.50). (Figs. 23–23e)................ S. normanna sp.n.
12’ Elytra less rounded to side. Rostrum more slender (RL/RW 1.29–1.33).......................................... 13
13. Sides of pronotum sinuate. Elytral setae semierect. (Figs. 18–18e).................................. S. angelinii sp.n.
13’ Sides of pronotum weakly rounded. Elytral setae recumbent. (Figs. 16–16e, 16 ’–16’e)....... S. gestroi A. & F. Solari, 1923