Blue dasher vs Common whitetail
These two are easy to mix up. Here's how to tell a blue dasher from a common whitetail, and whether either one bites or stings.
Blue dasher
Pachydiplax longipennis
Common whitetail
Plathemis lydia
≠The key differences
Male whitetails have a broad, chalky-white abdomen and a wide black band across the middle of each wing; blue dashers have a slimmer blue abdomen and clear wings.
⚖︎Side by side
| Blue dasher | Common whitetail | |
|---|---|---|
| To humans | Non-toxic | Non-toxic |
| Size | Length about 28-45 mm; wingspan about 50-70 mm | wingspan 6-8 cm, body length 35-45 mm |
| Colours | Powder blue, Dark brown/black, Yellow-green, Clear wings | Powdery white, Dark brown, Tan, Clear/transparent |
| Family | Libellulidae | Libellulidae |
| Habitat | Still or slow freshwater: ponds, marshes, ditches, lake margins and occasionally slow streams with emergent vegetation | Ponds, marshes, slow streams, ditches and other still or slow-moving freshwater with nearby perches and emergent vegetation |
| Range | Widespread in the United States and southern Canada, common south into Mexico and parts of Central America; most abundant in lowland and disturbed wetlands | Widespread across much of the United States and southern Canada; also found in parts of northern Mexico |
| Active | Active from late spring through early autumn (peak in summer); diurnal, most active in warm, sunny weather | Late spring through early fall (varies by latitude); most active during warm daylight hours |
| Pest? | No | No |
🔍How to spot a blue dasher
- Males: powder-blue abdomen with a black tip, striped dark thorax, white face and metallic green eyes
- Females and young males: brown-and-yellow striped thorax and dark abdomen with yellow dashes
- Perches on plant stems or bare ground with abdomen slightly raised; wings clear with small dark pterostigma
🔍How to spot a common whitetail
- Mature males have a strongly pruinose (powdery) white abdomen contrasted with a darker thorax.
- Females and immature males have a brown abdomen with pale side dashes and three dark spots on each wing.
- Males have a wide black band across the middle of each wing plus a dark base; overall stocky skimmer build.
- Perches on emergent vegetation or flat surfaces near still water; males often hold territory.
?Frequently asked questions
What is the difference between a blue dasher and a common whitetail?
Male whitetails have a broad, chalky-white abdomen and a wide black band across the middle of each wing; blue dashers have a slimmer blue abdomen and clear wings.
Is a blue dasher or a common whitetail more dangerous?
Blue dasher: Non-toxic. Common whitetail: Non-toxic. Blue dashers do not bite people except in extreme, rare handling situations; any bite would be a mild pinch only. Common whitetails are not venomous and pose no medical threat.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.