Had my first Four-spotted Chasers of the year today. They have an extra wing spot on each wing unlike the other chasers. This species is unusual in having no easy visual clue regarding sex. Just by chance, they were a male and female so how did I make the decision? First and foremost, you need a very close view when at rest or a closeup photograph.
It's all about the anal appendages, the male is built for clasping hold of the female when mating...
the 'claspers' flare outwards at the tip of the abdomen.
In the female, the appendages are more widely set. They converge at the tip (or as here they are parallel).
They converge at the tip (or as here they are parallel).
They either converge at the tip or as seen here, are parallel.
The shape of the abdomen holds some clues as well but that's another story...