Key to genera of world Sclerogibbidae

Females

1. Macropterous (fossil species) (Fig. 14; fig. 1 in Engel & Grimaldi 2006).............................................................................................. Pterosclerogibba Olmi and Sclerogibbodes Engel & Grimaldi

- Apterous or micropterous (extant and fossil species) (Figs 4–8, 13).............................................. 2

2. Micropterous (Figs 1, 2, 4, 5); frons not produced over base of antennae (antennal toruli not concealed in dorsal view) (Figs 2, 4, 5); palpal formula 6/4.......................................................... Protosclerogibba gen. nov.

- Apterous (Figs 6–9); frons produced over base of antennae (antennal toruli concealed in dorsal view) (Fig. 9); palpal formula from 2/1 to 6/3, never 6/4............................................................................... 3

3. Mesosoma crossed by a straight suture separating the metanotum and scutellum from the propodeum and distinctly crossing the body (Fig. 6); metanotum composed of two very large pieces situated on the sides of the scutellum (Fig. 6); head usually with 2 ocelli (Fig. 6), rarely with 3 ocelli; eyes usually small, approximately situated half-way in the head lateral margin (Fig. 6); occasionally eyes larger and situated in the posterior third of the head; anterior flat surface of hypostomal bridge as long as first antennal segment, or slightly shorter; tibial spurs 1/1/2............................. Caenosclerogibba Yasumatsu

- Mesosoma never crossed by a straight suture separating the metanotum and scutellum from the propodeum (Figs 7, 8); metanotum usually composed of two narrow pieces situated on the sides of the scutellum (Figs 7, 8); occasionally the above pieces are large, but in this case the suture separating the metanotum and scutellum from the propodeum is always curved; head with 3 ocelli (Figs 7, 8); eyes always large, situated in the posterior two thirds of the head (Figs 7, 8)...................... 4

4. Tibial spurs formula 1/1/2; anterior flat surface of hypostomal bridge as long as first antennal segment, or slightly shorter (Figs 10, 11)............................................................................. Probethylus Ashmead

- Tibial spurs formula 1/2/2; first antennal segment at least twice as long as anterior flat surface of hypostomal bridge (Fig. 12)...................................................................... Sclerogibba Riggio & De Stefani-Perez