Gongylonema spp. are covered by wart-like cuticular bosses that are especially prominent near the anterior end of the worm. In bovids, Gongylomena pulchrum parasitizes the esophagus whereas G. verrucosum prefers the rumen. The worms weave themselves into the mucus membranes of the host in curious, regular tracts (left). Nonetheless, they are considered to be relatively harmless. Animals become infected by ingesting arthropods such as cockroaches or dung beetles that harbor infective third stage larvae.