| Xiphosomella setoni Johnson, 1969 |
| Xiphosomella tabascensis Morley, 1913 |
| Xorides Latreille, 1809 |
| Xorides (Exomus) Townes, 1960 |
| Xorides (Exomus) humeralis (Say, 1829) |
| Xorides (Exomus) humeralis subsp. chiricensis Townes, 1960 |
| Xorides (Exomus) humeralis subsp. excomptus Townes, 1960 |
| Xorides (Exomus) humeralis subsp. mexicanus Townes, 1960 |
| Xorides (Exomus) humeralis subsp. sierrae Townes, 1960 |
| Xorides aegypticus Walker, 1871 |
| Xorides cerbonei Porter, 1978 |
| Xoridinae Shuckard, 1840 |
| Xylonominus Clement, 1938 |
| Xylonomus Gravenhorst, 1829 |
| Xylonomus (Moerophora) Förster, 1869 |
| Xylonomus australis Cresson, 1970 |
| Xylonomus lavallensis Provancher, 1874 |
| Xylonomus piceatus Rohwer, 1913 |
| Zacharops Viereck, 1912 |
| Zachrestinus Enderlein, 1921 |