Aha! Just read about this here. The red things on the ventral thorax are parasitic mites. I think they may be water mites, genus Arrenurus -- see bugguide.net/node/view/84930. This was my 1st foray into dragonflies (they are officially cool), & I knew absolutely nothing about them. So when I saw some of these with red & some without, I figured they were male & female of the same species. It was only when I got home & looked them up that I discovered that the green ones were all female; the male is blue. In fact, I didn't get a shot of a male because I confused it with the Spangled male -- didn't realize there were 2 different species. Then I thought maybe the red things were eggs... nope! Anyway, here's a shot without the mites.