Promethea Silkmoth (Callosamia promethea)

The Promethea Moth is common in most of its range, which includes south-central Hastings County in Ontario. Yet despite their large size and striking appearance these moths are seldom encountered due to their nocturnal habits, and when resting they hang out the trees where their patterning makes them difficult to spot. (Another seldom seen Saturniid is the Io Moth – live moths are few and far between but it's not uncommon to find the remnants of the wings of individuals that have been bagged by bats.)

This pair stood out like a sore thumb, but then again, as a rule one doesn't expect to see a pair of these moths in the grass at the edge of a parking lot ensuring their genes are passed on to the next generation. In the case of Callosamia promethea this happens from late afternoon until evening, and the eggs are laid at night.

The larvae eat the leaves of a variety of trees – maple, cherry, birch – this caterpillar was found on White Ash. In our area they pupate in early autumn, and the adults emerge in late May or early June to begin the cycle anew. Adult Promethea Moths don't have functional mouthparts and live only a few days, surviving on the energy stored in their tissues from their time as a caterpillar.

Promethea Moths are sexually dimorphic, with the male being smaller and much darker than the female, and lacking the chevron-shaped spots on the upper surfaces of its wings.

The wingspan varies from 75 mm to 95 mm, but the female seemed larger than this.

As if finding a mating pair of these large moths wasn't surprise enough, not fifteen meters away was another female taking shelter in an alcove. She looked like she had only recently emerged and was moved to the safety of a nearby park, as there was too much traffic, both pedestrian and vehicular, in the area.

To learn more about this beautiful insect visit Butterflies and Moths of North America.

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.

Dragons in the Shadows

Like most of its Baskettail and Emerald cousins (family Corduliidae) the Stygian Shadowdragon is a medium sized dragonfly about 50 mm in length. In contrast to its sun-loving relatives and odonates in general this dragonfly is crepuscular, coming out to forage over fast-flowing water at dusk and flying into the early hours of the evening.

Due to its nature the Stygian Shadowdragon is seldom encountered and has earned an undeserved reputation for being rare, but the numbers of exuviae found on rocks rising out of the water and bridge piers indicate otherwise. True to form this teneral male was spotted hanging out in a shady spot.

A better look at Neurocordulia yamaskanensis – needless to say the dragonfly was handled with great care. It wasn't fresh out of its larval exoskeleton, but it's not fully mature either, so it was studied for as short a time as possible to avoid damaging its relatively soft body.

This is not a boldly colored insect, with pale yellow markings on the thorax and abdomen, and an amber tint at the base of the wings, looking much like a faded Baskettail.

Lateral, oblique and ventral aspects of the terminal appendages. The Broad-Tailed Shadowdragon (Neurocordulia michaeli) would have a tiny spine on the ventral side of the cerci.

A feature that stood out immediately in the field but not mentioned in my books is that the cerci are somewhat flattened (unlike the cerci of, for instance, a Common Baskettail) and have a bit of a twist to them.

In hindsight the Stygian Shadowdragon depicted above was not the first encounter. On May 31st, 2014 during a tour of the Point southeast of town we had observed what looked like a washed-out teneral male Baskettail. I was unable to approach closely enough to capture or photograph the dragonfly, but Jason King had acquired an image and the mystery dragonfly proved to be a Stygian Shadowdragon.

Two sightings within a few days suggested the Stygian Shadowdragons were molting and transforming into adults, and this prompted a hunt for exuviae and/or emerging tenerals.

The exuviae, collected on June 03, 2014, were found approximately 2 meters from the water (that includes horizontal and vertical distance) on the pier of a bridge crossing the Moira River at Louisa Steet in Tweed, Ontario. The first sets of images are not the best, they were taken underneath the pier on a cloudy day using the flash.

Length is about 23 mm give or take.

Exuviae Number 1

Exuviae Number 2

The following day was sunny, making it possible to acquire sharper images. These macros of Exuviae Number 2 illustrate the critera used to determine that the exoskeleton once belonged to Neurocordulia yamaskanensis – the deep, rounded crenations on the labial palps ...

... rounded dorsal spines pointing backwards ...

... divergent lateral spines on S8, and lateral spines on S9 that do not extend past the cerci.

On June 05, 2014 another exuviae about 25 mm long was discovered on the pier of the old railroad (now the trans-Canada Trail) bridge spanning the Moira River, about 10 meters from the shoreline.

Identification of odonate naiads and exuviae can be tricky and isn't covered further than the family level in field guides. The exuviae were identified to species level with this Key to Larvae of Michigan Corduliidae.