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 (a), then the middle leg (b), then the hind leg (c). 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.^[1] This character is especially useful at family rank and higher.^[2]

Diagram of a typical insect leg