The stylostome is a funnel- or channel-like structure formed in response to trombiculid mites. Trombiculid mites are found throughout the world. The unusual life-cycle of trombiculid mites is described in the section on blood-sucking mites. Trombiculid mites go through a lifecycle of egg, larva, nymph, and adult. Trombiculid mites (chiggers) also feed on blood, but only in the larval stage.