Tarsal formula
A tarsal formula states the number of segments of an insect's tarsi as three 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" as found in the Trictenotomidae means there are five segments in the fore leg's tarsi, five segments in the middle leg's tarsi, and four segments in the hind leg's tarsi. This character is especially useful at family rank and higher.