Key to the adult males of known species of Xylococcidae

1. Tibial spurs clavate; antennae each longer than 2.4 mm ........................................................ 2

- Tibial spurs not clavate; antennae each less than 2.0 mm long......................... Xylococculus betulae (Pergande)

2. Loculate pores with loculi all of similar size; loculi separated by broad septa; tergites on abdominal segments I–V narrow................................................................................. Xylococcus japonicus Oguma

- Loculate pores with uneven-sized loculi; loculi separated by fine septa; tergites on abdominal segments I–V broad................................................................................ Xylococcus castanopsis Wu & Huang