In wireworms most of the sensory nerve system terminates peripherally in seven types and 20 sub-types of sense organs. All are represented in the head and its appendages. The main types of sensilla are thick-walled hair, campaniform, mandibular pore canal, scolopophorous, peg or thin-walled hair, and sensory plate organs, and a large antennal sensory appendix. The first three types are innervated by one, the fourth by two, the fifth and sixth by four, and the last by more than four neurones.