Enallagma basidens
In 3 days ~10% in a week ~20%
The double-striped bluet (Enallagma basidens) is a species of damselfly in the family Coenagrionidae. This species grows to lengths 21–28 mm. Its common name from the peculiar black shoulder stripe, which is divided in two by a thin blue stripe. This is the key identification characteristic; no other damselfly has a shoulder stripe that looks like this one.
Mature males have an abdomen that alternates black and blue. The final segment of the abdomen is blue below and black above, while segments 8 and 9 are all blue. Females and immatures are tan to olive or brown, but like the mature males they have the divided shoulder stripe.
These damselflies are most typically found alongside lakes and ponds, but are occasionally found next to slow-moving streams, too. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Big Bend National Park | 🇺🇸 United States | |
| 2 | Shenandoah National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Dallas | 🇺🇸 United States | |
| 2 | Austin | 🇺🇸 United States | |
| 3 | San Antonio | 🇺🇸 United States | |
| 4 | Houston | 🇺🇸 United States | |
| 5 | Chicago | 🇺🇸 United States | |
| 6 | Washington | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Double-Striped Bluet sighting in Houston on a given day, based on 24 verified sightings from GBIF citizen-science data. It is the 495th most-seen of the 1057 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Double-Striped Bluet in Houston on a given day, so our monthly data shows no clear season.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Double-Striped Bluet sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
4th of 6
Of the 6 cities where we can rate Double-Striped Bluet sightings, Houston ranks 4th at under 5%. The best odds are in Dallas (United States, about 10%), Austin (United States, about 10%) and San Antonio (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Double-Striped Bluet is recorded against all the insects logged in Houston (24 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
