What is "polyphaga"

Polyphaga is the largest and most diverse suborder of beetles. It comprises 144 families in 16 superfamilies, and displays an enormous variety of specialization and adaptation, with over 300,000 described species, or approximately 90% of the beetle species so far discovered.

Key characteristics of Polyphaga are that the hind coxa (base of the leg), does 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.