- This family is known
as the Emeralds. Most of the members of this family have a metallic green
or bronze color. The abdomen is usually long and slender. Most members of
this family are medium sized, but there are a few that are small. In most
species the eyes are bright emerald green.
- In North America, 49
species from seven genera belong to this family. In Idaho, there are four
species in two genera.
- These dragonflies tend
to occur farther north or at higher elevations than other dragonflies, except
the Darners and Whitefaces.
- The naiads of these
dragonflies are usually found in streams, bogs, or coldwater lakes. They are
not found where oxygen content is low or water quality is otherwise poor.
Because of their occurrence in colder climates, the nymphs may take several
years to mature.
- The ovipositor of the
females is greatly reduced, and the females lay eggs (oviposit) by dipping
the tip of the abdomen in the water while hovering just above the surface.
The females oviposit by themselves without a male in attendance.
- The naiads are short
and squat, and don't move around much. Instead, they prefer to lay concealed
on the bottom and wait for prey to come to them. As a result they are much
less vulnerable to predation by fish than other more active naiads such as
- The naiads emerge at
night. Emergence is a slow process and the newly emerged adults are very vulnerable
to predators. They usually crawl vertically on to vegetation and emerge while
only one North American species in this genus. These dragonflies are a solid
metallic green with no markings on the sides of the thorax. The wings are unmarked.
The naiads have stripes on the thorax.
are metallic green with gold dots or stripes on the sides of the thorax. The
face is usually at least partly yellow. Members of this genus range farther
north than any other dragonflies. The naiads are uniform in color and are distinguished
from those of Cordulia by the lack of stripes on the thorax.
Somatochlora minor- Ocellated
Somatochlora semicircularis- Mountain
Written by Mark Lung and Stefan
Page design by Ean Harker 2001.
Original images provided by Dennis Paulson,©2001