Clerid beetles fall under the suborder Polyphaga. Key characteristics of Polyphaga are that the hind coxa (base of the leg), do not divide the first and second abdominal/ventral plates which are known as sternites. Also, the notopleural suture (found under the pronotal shield) is not present.[1] To further identify Clerid beetles, a few additional characteristics need to be examined.
5 rear leg tarsomeres of Tillus elongates (Tillinae)
Clerid beetles have unique legs that help to distinguish them from other families. Their tarsal formula is 5–5–5, meaning that on each of the front, middle and hind legs there are 5 tarsomeres (individual subsegments of the feet/tarsi).[1] One or more of these subsegments on each leg is typically lobed, and the 4th tarsi is normally difficult to distinguish. Furthermore, an important feature that eliminates many other families of beetles is that clerids' front coxae (base of the leg) expose the second segment of the legs known as the trochanter.[1]
The second defining characteristic of the family Cleridae is that clerids never have eversible vesicles (small usually hidden balloon-like structures thought to be scent glands) on their abdomen and pronotum. This characteristic distinguishes them from a similar family Melyridae which sometimes has these glands.[1] This trait is very important in correctly differentiating checkered beetles from Melyridae.