Abstract
Observations on the host relations of Opisthopus transversus Rathbun lead us to conclude that its abundance in nature is due especially to its ability to associate with a wide variety of hosts. By virtue of its promiscuity, it would appear to have enhanced its survival and extended its known range significantly. There is evidence presented that suggests that Opisthopus transversus may be exerting pressure on another member of its family, Pinnixa barnharti in competition for space (host association).