Key to Palaearctic genera of Diprioninae

1. In dorsal view, mesoscutellar appendage including its anterior margin visible throughout along posterior margin of mesoscutellum (Figs 5A, C); anterior end of lateral ocellus located anterior to level of posterior end of median ocellus (Fig. 2C); malar space narrower or wider than width of median ocellus; claws with inner tooth...................................... 2

- In dorsal view, mesoscutellar appendage concealed below mesoscutellum entirely or except for narrow apex, rarely visible except for most of its anterior margin; anterior end of lateral ocellus located anterior or posterior to level of posterior end of median ocellus; malar space about as long as or wider than width of median ocellus; claws with or without inner tooth.... 4

2. Abdomen dorsally distinctly microsculptured; posterior hind-tibial spur shorter than first hind-tarsomere exclusive of pulvillar pad....................................................................................... Prionomeion

- Abdomen dorsally polished; if abdomen weakly microsculptured, posterior hind-tibial spur as long as or longer than first hindtarsomere............................................................................................ 3

3. In female antenna, middle flagellomeres each with two ramus; posterior hind-tibial spur often as long as or longer than first hind-tarsomere............................................................. Nesodiprion in part (most species)

- In female antenna, middle flagellomeres each with one ramus and with small convexity on inner side; posterior hind-tibial spur shorter than first hind-tarsomere.................................................................. Neodiprion

4. Claws with inner tooth................................................................................. 5

- Claws without inner tooth. [Anterior end of lateral ocellus located anterior to level of posterior end of median ocellus; hind wing with section of vein 1A between crossveins a and cu-a less than 1.3 × width of cell 1A; abdomen dorsally polished or microsculptured.]............................................................................ Microdiprion

5. Abdomen dorsally microsculptured; anterior end of lateral ocellus located anterior to level of posterior end of median ocellus; hind wing with section of vein 1A between crossveins a and cu-a often more than 1.5 × width of cell 1A............... 6

- Abdomen dorsally polished; anterior end of lateral ocellus located slightly behind level of posterior end of median ocellus; hind wing with section of vein 1A between crossveins a and cu-a at most 1.5 × width of cell 1A............................................................................................ Nesodiprion in part (only N. shinoharai)

6. Female flagellum in lateral view abruptly narrowing at apex and dorsally serrate; male flagellum biramose except for apical five to six flagellomeres and most basal one....................................................... Macrodiprion

- Female flagellum in lateral view gradually narrowing toward apex and dorsally scarcely serrate; male flagellum biramose except for apical one to three flagellomeres and most basal one................................................ 7

7. Metascutellum length 0.8 × cenchrus width or longer................................................... Diprion

- Metascutellum length 0.7 × cenchrus width or shorter................................................... Gilpinia