| Tenthredoides Cresson, 1865 |
| Tetrasphaeropyx Ashmead, 1889 |
| Tetrasphaeropyx pilosus Cresson, 1872 |
| Theracmion Holmgren, 1872 |
| Therobolus Förster, 1862 |
| Tinaria Provancher, 1886 |
| Tinaria pilicornis Provancher, 1886 |
| Tolbia Cameron, 1907 |
| Toxoneura Cresson, 1887 |
| Toxoneura floridana Ashmead, 1894 |
| Toxoneuron Say, 1836 |
| Toxoneuron aethiops Cresson, 1868 |
| Toxoneuron bicolor Szépligeti, 1902 |
| Toxoneuron mexicanus Masner, 1976 |
| Toxoneuron orizabae Cresson, 1873 |
| Toxoneuron thoracicum Cresson, 1873 |
| Trachionus Haliday, 1833 |
| Triaspis Haliday, 1835 |
| Triaspis azteca (Cresson, 1873) |
| Triaspis virginiensis (Ashmead, 1889) |