Key to the species of the tribe Synanthedonini of Taiwan

1. Large species, body length greater than 14 mm, forewing length greater than 11 mm ......................... I. gryphus

- Small species, body length less than 11.5 mm, forewing length less than 10 mm .................................... 2

2. Abdomen with more than 4 yellow stripes, length of tegumen-uncus 2.3−3.1X saccus; scopula long, equal to length of tegu- men-uncus...........................................................................................3

- Abdomen with less than 3 yellow stripes, length of tegumen-uncus 4.0−4.9X saccus; scopula short, about 3/ 4X length of tegu- men-uncus........................................................................................... 5

3. Forewing yellow proximally, exterior transparent area broad, outer margin convex........................ P. formosicola

- Forewing black proximally; exterior transparent area narrow, outer margin truncate or nearly truncate...................4

4. M 2 in forewing exterior transparent area approximately 1/2 length of M 2 in apical area..................... P. dortmundi

- M 2 in forewing exterior transparent area approximately 1/4 length of M 2 in apical area........................ P. weiyui

5. Brown scalings present along hindwing termen; larva as borer in acorn, feeding on kernel.................. K. glansvorax

- Hindwing thoroughly transparent; larva as borer in stem, feeding on callus tissue................................... 6

6. Body mostly black with blue sheen, abdomen with white stripes........................................ S. ceraunus

- Body mostly without blue sheen, abdomen with yellow stripes.................................................. 7

7. Abdomen tergite 4 with a broad yellow stripe; gnathos duplex......................................... S. auritincta

- Abdomen tergite 4 with a narrow yellow stripe; gnathos simple.......................................... S. phoenix