Stephanidae, Leach, 1815

Engel, Michael & Ortega-Blanco, Jaime, 2008, The fossil crown wasp Electrostephanus petiolatus Brues in Baltic Amber (Hymenoptera, Stephanidae): designation of a neotype, revised classification, and a key to amber Stephanidae, ZooKeys 4 (4), pp. 55-64 : 62

Revised key to Baltic Amber Stephanidae

1 First metasomal tergum and sternum fused laterally to form distinct petiole ( Denaeostephanus Engel & Grimaldi ) ..........................................................2

– First metasomal tergum and sternum not fused, separated by small membranous area (“pseudo-petiole”) ( Electrostephanus Brues ) .................................. 3

2 Metafemur with two principal teeth, one near midlength and one near apical quarter............................................................ D. sulcatus (Aguiar & Janzen)

– Metafemur with three principal teeth, one near proximal quarter, one near midlength, and one near apex...................................... D. tridentatus (Brues)

3 Forewing vein Rs+M b absent or scarcely present; bullae absent ...................4

– Forewing vein Rs+M b distinctly present; bullae present................................. ...................................................................... E. neovenatus Aguiar & Janzen

4 Forewing 2Cu a and 2Cu b absent or nebulous; Rs+M b absent or scarcely present; pseudo-petiole short, one-half mesosomal length or less; gaster relatively robust, distinctly thicker than pseudo-petiole; metafemur with two principal teeth, one near midlength, one near apex; antenna with fewer than 20 articles; smaller species, males 4–7.1 mm in length ................................5

– Forewing 2Cu a and 2Cu b present and tubular; Rs+M b absent; petiole elongate, nearly as long as mesosoma; gaster slender, tapering gradually from pseudopetiole to apex; metafemur with three principal teeth, one proximally, one near midlength, one near apex; antenna with 23 articles; larger species, males 9.0–10.0 mm in length (subgenus Electrostephanodes n. subgen.) ................. ......................................................................................... E. petiolatus Brues

5 Male antenna with 14 articles; second through fourth flagellar articles each widened apically and about three times longer than wide; forewing Rs+M b scarcely present (exceedingly short), 2Cu a and 2Cu b nebulous; moderatesized species, males 6.0– 7.1 mm in length ........................... E. janzeni Engel

– Male antenna with 17 articles; second and third flagellar articles each widened apically and 2.5 times longer than wide, fourth flagellar article not widened apically and three times longer than wide; forewing Rs+M b, 2Cu a, and 2Cu b absent; smaller species, male 4.2 mm in length ............... E. brevicornis Brues