This large male blister beetle was crossing the trail. When I knelt down to photograph it I saw it had a tiny beetle attached to its abdomen. Thanks to Bug Guide I discovered this interesting information: "Adults of many genera, notably Pedilus, are attracted to cantharidin (males seek out blister beetles, climb onto them and lick off the cantharidin the blister beetles exude and use the blistering agent to impress a female of their own species who then mates with them, whereupon most of the cantharidin is transfered to the female in the form of a sperm packet. The eggs the female subsequently lays are coated with cantharidin to protect them from being eaten before they hatch. -Jim McClarin, 26.iii.2006)"

These beetles are also called oil beetles because they emit a rather stinky oily substance when disturbed. This can cause a blistering on the skin if it gets on you. The females are much larger than the males, and the males are a good size.