Nice fish.
When you saw one dragonfly eating the other it may well have been the female chewing off the male's head. They need to do this for the enzyme (or is it the some protein...) to complete the mating "process". I am sure there are better folks on this board to explain it....
I was hiking in the Trinity Alps several years ago and saw this happen about five times on one section of trail. My hiking partner was a biologist and she explained the process.....with a good warning too!
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