Key to the Sphaeropthalma imperialis species­group

Males

1. Sternal felt line absent ................................................................................................... 2

­ Sternal felt line present, tuft­like................................................................................... 3

2. Mandibles very broadly dilated, especially ventral portion apically, distally much wider than width at ventral angulation (Fig. 7); clypeus very deeply depressed below mandibular rims; wings yellowish­hyaline (Fig. 29) ............. S. megagnathos Schuster

­. Mandibles moderately dilated, distally little or scarcely wider than at tooth (e.g., Fig. 6); clypeus moderately depressed; wings dark brown to black (Fig. 26)........................ ....................................................................................................... S. edwardsii (Blake)

3. Integument of second and following metasomal segments orange (Fig. 27); second segment with mostly orange pubescence (Fig. 27); mesonotum and often pronotum dorsally deeply ferruginous (Fig. 27); head rounded posteriorly, short and contracted behind eyes (Fig. 1); clypeus at or slightly depressed below mandibular rim................ ........................................................................................................ S. imperialis (Blake)

­ Second metasomal segment and mesosoma black or blackish (Fig. 28); second segment with pubescence variable from orange to silver; mesosoma entirely black (Fig. 28); head quadrate posteriorly, long and parallel behind eyes (Fig. 2); clypeus very deeply depressed below mandibular rim ....................................... S. marpesia (Blake)

Females

(Note: the female of S. megagnathos remains unknown)

1. Mesosoma as broad as long (Fig. 3); flagellomere I less than 2X length of pedicel, subequal in length to flagellomere II; pubescence of head, mesosoma and metasoma not concolorous (Figs. 20, 22, 25) ...................................................................................... 2

­ Mesosoma longer than broad; flagellomere I more than 2X length of pedicel, noticeably longer than flagellomere II; pubescence of head, mesosoma and metasoma reddish to orange or yellow, concolorous except plumose fringes on metasomal tergites whitish (Fig. 24) ............................................................................ S. edwardsii (Blake) 2. Mesosoma with yellow setae (Fig. 25); T2 not concave anteromedially; antennal scrobe having a well­developed dorsal carina ................................. S. marpesia (Blake)

­ Mesosoma with black to reddish setae (Fig. 20, 22); T2 appearing concave anteromedially (Fig. 4, 21); antennal scrobe lacking a well­developed dorsal carina.............. ........................................................................................................ S. imperialis (Blake)