- This is an important tribe of beetles, including families with four malpighian tubes and only five or six abdominal sterna, while in the thorax there is a backwardly directed process of the prosternum that fits into a mesosternal cavity.
Sternal area broad, with prosternal, two mesosternal, and metasternal plates, the prosternum projecting forwards beneath the coxae of the 2nd pair of appendages.
A, Prosternum of prosoma.
Prosternum underlying the proboscis.
Proboscis free, not supported from below by either the prosternum or the basal segments of the appendages of the 2nd pair.
Sternal elements of prosoma almost entirely absent, traces of a prosternum and metasternum alone remaining.
Rostrum free, not supported by either the prosternum or the basal segments of the appendages.
In the thorax the pronotum and prosternum are closely associated with the mesothorax, but the pleura of the prothorax are usually shifted far forwards, so that the forelegs are inserted just behind the head.