The Dragonflies of Drag Lake

Drag Lake is located about 7.25 km west of Tweed , at 44.443129°, -77.391084° along the trans-Canada Trail according to Google Maps. The lake appears to be rock-bottomed – calcerous, judging by the surrounding geology – with relatively shallow water, and the parts of the shoreline are bordered by marshes. Some odonates can be particular with regard to their habitat requirements and for whatever reason the Dusky Clubtail is plentiful at this body of water.

With a length of 50 mm ± 5 mm, Gomphus spicatus is larger than the Lancet Clubtail (44 mm ± 5 mm). As its name suggests the Dusky Clubtail tends to be darker than its cousin, lacking the Lancet Clubtail's yellow dorsal stripe on S9.

However, the dragonflies can vary in color and Gomphids are notorious for their mutable chromatic complexions in any event, with yellow becoming green and eventually changing to bluish-gray with increasing age. Both the Dusky and Lancet Clubtails can sport a pale yellow streak on S9 making this unreliable means of separating the two species. For a positive ID it's necessary to examine the claspers and/or genitalia.

Like most Gomphidae a.k.a. Clubtails, Dusky Clubtails perch on the ground or other horizontal surfaces such as low leaves. They are fairly tame (the individuals in these photos were captured by hand) and can often be approached closely, whereupon the lateral spines on the male's cerci are clearly visible.

The cerci also have a distinct ventral spine.

The male's secondary genitalia, looking at this picture the words such as baroque, labyrinthine and convoluted come to mind ...

The abdomens of the females tend to be more robust than those of males. The distribution of the sexes was rather odd, with thirty one males but only two females being encountered.

A macro of the female's genital plate.

There were plenty of exuviae scattered along the shoreline but none belonging to the Dusky Clubtail were in evidence. Although unconfirmed as yet (the images are at BugGuide.Net) the largest exoskeletons probably belonged to Epitheca princeps, the Prince Baskettail – but no Prince Baskettails were seen flying.

EDIT ... the response from BugGuide.Net: if there are four setae on the edges of the palps (which there are) the exuviae belong to Epitheca princeps. Also, according to this key at Odonata Larvae of Michigan the dorsal surface of prementum should be setose, which is the case in the specimens. So Epitheca princeps it is.

Four teneral female Calico Pennants (Celithemis elisa) were also sighted perching in the tall grasses, and apparently this dragonfly also finds the atmosphere of Drag Lake convivial. The Calico Pennant is not uncommon at other wetland habitats in south-central Hastings County, but in the coming summer months uncountable numbers of these colorful little skimmers can be found flying at Drag Lake.

The Belted Whiteface (Leucorrhinia proxima) and the Frosted Whiteface (Leucorrhinia frigida) are another pair of dragonflies that can be tough to distinguish at a glance. They are very similar in size, coloration and patterning, and both species develop pruinosity on the first few abdominal segments.

This Belted Whiteface was captured near a marsh a couple of kilometers east of Drag Lake, and examination of the hamules (top) and claspers (bottom) is the best means of distinguishing it from the Frosted Whiteface.

American Emerald (Cordulia shurtleffii)

Another dragonfly to add to the list of species that can be seen at the Stoco Fen ... the American Emerald (Cordulia shurtleffi). The key field marks of this species are the whitish ring between S2 and S3, and the cross-vein in the forewing triangle.

The eyes of this immature female will turn a deep green with increasing age.

A male American Emerald, encountered two years ago at Stoco Lake; this dragonfly can also be found patrolling sunlit clearings along the trail.

A lateral view of another male's terminal abdominal segements – note the forked lower clasper.

In the realm of odonate identification, the male's claspers are the final word as to species. The following images depict the claspers of a male dragonfly that at first glance appeared to be a Lancet Clubtail (Gomphus exilis). But it's difficult to separate this species from the closely related Dusky Clubtail (Gomphus spicatus) and Ashy Clubtail (Gomphus lividus) solely on the basis of body coloration and patterning. So let's have a close look at the claspers ...

When viewed in lateral profile, the upper claspers of this dragonfly bear a distinct ventral spine.

And looking at the upper claspers from above, a prominent lateral spine is visible. So our specimen isn't a Lancet Clubtail after all, these features are characteristic of the Dusky Clubtail (Gomphus spicatus). Case closed.

Three of our local Baskettails are also easily confused (there's information on how to sort them out at A Fetch of Dragonflies). But the distinctively downward bent claspers of this male are clearly visible from this angle – this is a Beaverpond Baskettail (Epitheca canis). The eyes are taking on a bluish tint with increasing age.