In all the Oregon Tiger Beetle populations I’ve observed, I’ve seen pairs mating. During mating and mate guarding, the male grips the female between the thorax and elytra with his jaws.
In image 1, note the aedeagus, the sclerotized sheath for the sperm-transfer tube, visible between the tip of the male’s abdomen and the tip of the female’s abdomen. In image 3, the aedeagus is also visible, either just extending from the male’s abdomen or almost withdrawn.
Image 5 shows a female laying eggs in the sand.
Image 6 is a slow-motion movie, one frame per two seconds, of a male withdrawing his aedeagus after mating. Note that the aedeagus swings through 180˚, then withdraws into the male's abdomen. According to Pearson, et. al., the aedeagus also rotates 90˚ on its axis when withdrawing into the abdomen.