The genus Somatochlora contains numerous species of medium to large dragonflies, including 16 known from Ontario. Even in appropriate habitat, these dragonflies rarely or never seem to be common, perhaps as they only visit breeding sites briefly and spend most of their time feeding in the canopy or in small forest clearings. I have encountered 6 species of Somatochlora this summer in Algonquin Park.
Clamp-tipped Emerald is a southern species near the northern limit of its range here in Algonquin Park, and is found in rocky forest streams. I caught these two patrolling a logging road near their breeding stream.
Male with his extraordinary claspers
Kennedy's Emerald is found in stagnant flooded sedge meadows.
Male Kennedy's Emerald
Lake Emeralds breed in deep nutrient-poor lakes, but disperse widely to forage.
Not the best photo, but this female is one of the few individuals of this fast-flying species I've actually managed to catch this summer.
Brush-tipped Emeralds use flooded sedge meadows like Kennedy's but usually seem to be found in areas with some flowing water. This small species is easier to catch than most Somatochlora.
This female was not hard to catch, as she was catching the deer flies buzzing around my head!
Male - you can see where the name Brush-tipped originates by looking at the claspers on the tip of the abdomen.
Occelated Emerald seem to be restricted, at least locally, to fairly rapid streams with steep dirt banks and little to no floating or emergent vegetation. They have been described in the literature as being found in shady forest streams but I have often found them along streams in sunny beaver meadows.
Williamson's Emerald seems to be much less specialised than the other members of their genus, but still are very uncommon.