1. Genal and Pronotal combs present .......... Ctenocephalides sp. ........ Go to: 3 & 4
2. Genal and Pronotal combs absent ........ Go to: 5 & 6

3. Head more elongate, First & Second spines of the Genal comb are about equal in length .......... Ctenocephalides felis (Cat Flea)
4. Head more rounded, First spine of the Genal comb is shorter than the second spine .......... Ctenocephalides canis (Dog Flea)

5. Head blunt and flat anteriorly .......... Echidnophaga gallinacea (Stick-tight Flea)
6. Head rounded ........ Go to: 7 & 8

7. Vertical chitinous rod present on the mesothorax, follicle of the ocular bristle is anterior to the eye .......... Xenopsylla cheopis (Oriental Rat Flea)
8. Vertical chitinous rod absent on the mesothorax, follicle of the ocular bristle is ventral to the eye .......... Pulex irritans (Human Flea)