Emeralds
What are they?
Emeralds are medium-sized dragonflies in the family Corduliidae. Although some species are quite common, they are difficult to identify and study as they spend long periods on the wing and usually hunt high overhead rather than from low perches. When they do come to rest, it is often amongst hidden, shady branches in trees, where they hang vertically. The commoner species are often found in large hunting gatherings where they patrol ceaselessly at treetop height. Mature males usually have brilliant emerald green eyes, the females have reddish brown eyes.
Identification
The habits of these dragonflies make them difficult to identify to species at times, but if caught or seen well through binoculars when perched, the color and pattern on the sides of the thorax and the shape and size of the cerci at the distal end of the abdomen should be studied.
Mocha Emerald Somatochlora linearis
Length: 2.4-2.8 inches. Flight time: Mid June to mid September. A species of uncertain status in Cape May County, having first been recorded here in 2010. This is a dark, poorly-marked species which breeds in muddy-bottomed forest streams and spends much of its time away from the water. It has been found along well-wooded trails in the middle to lower part of the county. The sides of the thorax are without pale stripes and the abdomen has only small, poorly-marked, orange spots.
| |
 |
 |
|
| |
|
|
|
 |
 |
| |
|
Treetop Emerald Somatochlora povocans
Length: 1.9-2.2 inches. Flight time: Early June to early September. A persistently high-flying species that may need to be caught temporarily to confirm identification in the hand. Common especially in the northern third of the county, where large feeding gatherings mix with Clamp-tipped Emeralds and feed at treetop height along woodland roadways. Note the pattern on the sides of the thorax and the shape of the male cerci or female ovipositor.
 |
|
 |
 |
| |
|
|
|
Clamp-tipped Emerald Somatochlora tenebrosa
Length: 2.1-2.3 inches. Flight time: Early June to late September. A persistently high-flying species that may need to be caught temporarily to confirm identification in the hand. Common especially in the northern third of the county, where large feeding gatherings mix with Treetop Emeralds and feed at treetop height along woodland roadways. Note the pattern on the sides of the thorax and the shape of the male cerci or female ovipositor.
 |
 |
 |
 |
| |
|
|
|