| 1a. | Thorax completely black | 2 |
| 1b. | Thorax with some red | 3 |
| | | |
| 2a. | Large ant, all black; gaster with appressed golden hairs | C. pennsylvanicus |
| 2b. | Smaller ant, variable in color (may have red on thorax), clypeus notched | C. nearcticus |
| | | |
| 3a. | Very large ant, with appressed golden hairs on gaster, red extending to 1st gastric tergite, warmer climates (mid-Connecticut and south) | C. chromaiodes
|
| 3b. | No appressed golden hairs on gaster, and no red on gaster | 4 |
| | | |
| 4a. | Thorax and legs completely red; gaster shiny and reflective | C. novaboracensis
|
| 4b. | Thorax with some black; legs rarely red | 5 |
| | | |
| 5a. | Clypeus notched; relatively small; gaster shining | C. nearcticus |
| 5b. | Hairs on propodeum denser than elsewhere; gular hairs few, short | C. herculeanus |
