Tarsal formula
Tarsal formula is the number of segments of the tarsi, which has 3 numbers a-b-c, starting with the fore leg, then the middle leg, then the hind leg. For example, a tarsal formula of "5-5-4" means there are 5 segments in the fore leg's tarsi, 5 segments in the middle leg's tarsi, and 4 segments in the hind leg's tarsi. This character is especially useful at family rank and higher.
