| Parent | Category | Figures | |
|---|---|---|---|
| 1 | Microtus | pennsylvanicus | 274 |
| 2 | Microtus | californicus | 200 |
| 3 | Microtus | pinetorum | 30 |
| 4 | Microtus | arvalis | 27 |
| 5 | Microtus | oeconomus | 18 |
| 6 | Microtus | townsendii | 15 |
| 7 | Microtus | montanus | 13 |
| 8 | Microtus | agrestis | 11 |
| 9 | Microtus | ochrogaster | 11 |
| 10 | Microtus | mexicanus | 11 |
| 11 | Microtus | savii | 8 |
| 12 | Microtus | longicaudus | 6 |
| 13 | Microtus | oregoni | 3 |
| 14 | Microtus | guentheri | 2 |
| 15 | Microtus | fortis | 2 |
| 16 | Microtus | richardsoni | 1 |
| 17 | Microtus | oaxacensis | 1 |
| 18 | Microtus | gerbei | 1 |
| 19 | Microtus | liechtensteini | 1 |
| 20 | Microtus | multiplex | 1 |
| 21 | Microtus | cabrerae | 1 |
| 22 | Microtus | canicaudus | 1 |
| 23 | Microtus | chrotorrhinus | 1 |
| 24 | Microtus | miurus | 1 |