The emeralds are among the most sought-after dragonflies because many are secretive, uncommon, and/or associated with "wild" northern habitats. Most are medium-sized (~2 inches), have bright green eyes (hence the group name), and are dark brown or black overall. Identifying emeralds usually relies heavily on (1) shape of the abdominal appendages (claspers in males, spout-like ovipositors in females), (2) shape of the thoracic side stripes, and (3) presence/absence of pale top spots on the abdomen. Emeralds can be found across a wide variety of water-based habitats and, with some exceptions, most are active in June-July. I found 13 species in 2008.