This shot shows the antenna-hooking behavior.

I found these guys while picking raspberries, but I didn't have my camera with me. So I plucked the raspberry leaf they were on -- thorns and all -- and carried it back to my house a couple of blocks away.

The male was nibbling gently on the back of the female's thorax the whole time. And he also kept up a steady tapping rhythm (~~90/min) with his antennae on hers, either both at once or alternating left and right sides. The male has a little extra orange hook tip on each antenna. When I looked at the photos, I discovered that, with each tap, he was hooking that tip under her antenna.

They occasionally (once a minute or so) stretched their abdomens out to a ~45-degree angle. Size measurements reflect length in that position.

Observed for 12 min total before I jostled the leaf & they flew off.