Siricinae, Billberg, 1820

Archibald, S. B. & Rasnitsyn, A. P., 2022, The early Eocene Eourocerus anguliterreus gen. et sp. nov. (Hymenoptera, Siricidae) from Republic, Washington, Zootaxa 5105 (2), pp. 289-295 : 293

Key to extant and extinct genera of Siricinae by forewing characters

1. Crossvein cu-a* antefurcal or slightly postfurcal (half or less its length distal to M+Cu)............................ 2

- Crossvein cu-a well postfurcal (more than half its length distal to M+Cu)........................................ 6

2(1). 2r-m lost, 3rm well developed.......................................................................... 3

- 2r-m and 3r-m both present (sometimes both weak or lost)................................................... 5

3(2). 2r-rs distal to 2m-cu, nearer end of long pterostigma........................................ Tremex Jurine, 1807

- 2r-rs placed more basally, near or basal to level of 2m-cu..................................................... 4

4(3). 2r-rs less than its length from pterostigmal end, membrane deeply infuscate basally and along anterior margin.......................................................................................... Afrotremex Pasteels, 1951

- 2r-rs more than its length from pterostigmal end, membrane pale, except darkened in anterior (especially mid-anterior) and apical parts of wing.............................................................. Eriotremex Benson, 1943

5(2). 1-M straight to gently curved........................................................... Xeris A. Costa, 1894

- 1-M strongly bent................................................................ Siricosoma Forsius, 1933

6(1). Cu1* distinct....................................................................... Sirex Linnaeus, 1758

- Cu1 absent or rudimentary............................................................................. 7

7(6). 1r-m long, joins R basal to Rs origin; cell 3rm shorter than high............................. Sirotremex Smith, 1988

- 1r-m short or absent, replaced with Rs+M................................................................. 8

8(7). 2r-m distal to 2m-cu.................................................... Xoanon Semenov-Tian-Shanskij, 1921

- 2r-m basal to 2m-cu.................................................................................. 9

9(8). 2r-m and 3r-m lost (former positions identifiable by slight bends of Rs and M); membrane with distinct transverse corrugation basal to 1-Rs, 1-M, cu-a, longitudinal corrugation distal to this............... Ypresiosirex Archibald & Rasnitsyn, 2016

- 2r-m and 3r-m present; wing membrane not transversally corrugated basally.................................... 10

10(9). 2r-rs distal to 2r-m.................................................................................. 11

- 2r-rs basal to 2r-m.................................................................................. 12

11(10). 1r-rs extremely short, almost its width long; Rs+M distinct although short....................... Teredon Norton, 1869

- 1r-rs distinct even though shorter than 2r-rs; Rs+M extremely short, almost its width long............................................................................................... Eoteredon Archibald, Aase & Nel, 2021

12(10). Length/width 3.2; apex angularly rounded; 1r-rs distinct although shorter than 2r-rs............ Urocerus Geoffroy, 1785

- length/width ca. 3.0; apex broadly rounded; 1r-rs extremely short, almost its width long........... Eourocerus gen. nov.