"Cimex lectularius" males have environmental microbes on their genitals. "Cimex lectularius" is an obligate parasite of humans. The bed bug, "Cimex lectularius", is an external parasite of humans. Cimex lectularius is a species of Cimicidae (bed bugs). "Cimex lectularius" aggregates under all life stages and mating conditions. These insects include "Cimex lectularius" (bed bug) and "Rhodnius proxlixus" (kissing bug). "Cimex lectularius" (the common bed bug) and "Cimex hemipterus".