New York Natural Heritage Program
Mocha Emerald
Somatochlora linearis (Hagen, 1861)
Insects

Identifying Characteristics [-]
Adult members of the family Corduliidae, or emeralds, have emerald green jewel-like eyes which come together to form a seam on top of their heads. Mocha Emeralds are large (2.3-2.6 inches), slender, and elegant dragonflies with black legs, a chocolate or mocha-colored thorax that has a greenish iridescence, and sometimes brown-tinted wings. They have a black abdomen with a whitish-yellow lateral (side) spot on abdominal segment 2 and pale orange-brown lateral (side) spots at the proximal ends (closest to the thorax) of segments 3-8. Male terminal appendages and female subgenital plates are distinctive among Somatochlora species when examined under magnification. Females (2.6-2.7 inches) are larger than males (2.3-2.4 inches), and their ovipositors are thorn-shaped and perpendicular from their abdomen. They are usually distinguished from other species of emeralds by their large size, elegant shape, brown-tinted wings, lack of markings on their thorax, and forested stream habitat.

Behavior [-]
Adult Mocha Emeralds hunt and feed in nearby fields or forest undergrowth, sometimes hunting in pairs. Flight behavior can be rapid with up-and-down and side-to-side undulations or slower with gliding movements. Males patrol up to 20-30 yards of stream looking for females (Dunkle 2000). Females oviposit (lay eggs) alone after mating by tapping the tip of their abdomen directly into wet mud or shallow water at the edges of the stream (Natural Heritage Endangered Species Program 2003, Nikula et al. 2003).

Diet [-]
Mocha Emerald larvae feed on smaller aquatic invertebrates and adults feed on insects which they capture in flight.
Mocha Emerald Images
click to enlarge
The Best Time to See
Somatochlora linearis are active from late June through early September in the northeast (Nikula et al. 2003). They are most active in early morning, beginning at dawn, and in the late afternoon to dusk (Dunkle 2000). Larvae may be found in appropriate habitats year-round.
J F M A M J J A S O N D
Present Reproducing
The time of year you would expect to find Mocha Emerald present (blue shading) and reproducing (orange shading) in New York.
Similar Species
  • Williamson's Emerald (Somatochlora williamsoni)
    Male Williamson's Emeralds are darker brown than Mocha Emerald males. Females have ovipositors (modified appendages used to pierce a substrate and lay eggs) that are longer than the length of abdominal segment 9, while the female Mocha Emerald's ovipositor is about as long as her abdominal segment 9. Both sexes of the Clamp-Tipped Emerald have thoracic stripes, while the Mocha Emerald is lacking of any markings on its thorax.
  • Clamp-Tipped Emerald (Somatochlora tenebrosa)
    If you look at the terminal appendages of a male Clamp-tipped Emerald from the side, there will be a circular gap between the appendages. This is distinctive from the Mocha Emerald and other emerald species. Female Clamp-tipped Emerald's have ovipositors (modified appendages used to pierce a substrate and lay eggs) that are longer than the length of abdominal segment 9, while the female Mocha Emerald's ovipositor is about as long as her abdominal segment 9. Both sexes of the Clamp-tipped Emerald have thoracic stripes, while the Mocha Emerald is lacking of any markings on its thorax.