| Xenoglossa (Xenoglossa) gabbii (Cresson, 1878) |
| Xenoglossa (Xenoglossa) gabbii subsp. crawfordi Cockerell, 1910 |
| Xenoglossa (Xenoglossa) gabbii subsp. gabbii (Cresson, 1878) |
| Xenoglossa (Xenoglossa) mustelina (Fox, 1893) |
| Xenoglossa (Xenoglossa) patricia Cockerell, 1896 |
| Xeromelecta Linsley, 1939 |
| Xeromelecta (Melectomorpha) Linsley, 1939 |
| Xeromelecta (Melectomorpha) californica (Cresson, 1878) |
| Xeromelecta (Melectomorpha) interrupta (Cresson, 1872) |
| Xeromelecta (Melectomorpha) larreae (Cockerell, 1900) |
| Xylocopa Latreille, 1802 |
| Xylocopa (Megaxylocopa) Hurd & Moure, 1963 |
| Xylocopa (Megaxylocopa) fimbriata Fabricius, 1804 |
| Xylocopa (Megaxylocopa) nautlana Cockerell, 1904 |
| Xylocopa (Neoxylocopa) Michener, 1954 |
| Xylocopa (Neoxylocopa) mexicanorum Cockerell, 1912 |
| Xylocopa (Notoxylocopa) Hurd, 1956 |
| Xylocopa (Notoxylocopa) tabaniformis Smith, 1854 |
| Xylocopa (Schoenherria) Lepeletier, 1841 |
| Xylocopa (Schoenherria) lateralis Say, 1837 |