The Black Blister Beetle is a slender, entirely black beetle frequently found in large aggregations on goldenrod and other composite flowers in late summer. Like all blister beetles, it contains cantharidin in its hemolymph, which blisters skin if the beetle is crushed. Horses can be fatally poisoned if they consume large numbers in hay.
Best time to see a Black Blister Beetle
The best time to see a Black Blister Beetle is August–September, when about 62% of U.S. sightings happen, based on 1,664 research-grade iNaturalist observations.
Not certain it is a Black Blister Beetle? What bug is this? walks through what to check first and the lookalikes that catch people out.
Recent Black Blister Beetle sightings near you
Live, research-grade observations from iNaturalist. Allow location to center the map on you.
Spot a Black Blister Beetle? Identify it instantly.
Point Huck at any plant, bird, or animal for an instant ID, its rarity, and a live map of where it is being seen near you.
Get HuckGet an alert when a Black Blister Beetle is spotted
Pick a park, state, or city and we’ll email you when one turns up there. One check a day, only when there’s something new.
Free. Unsubscribe from any email. See our Privacy Policy.
Love insects & arthropods? Get Huck field notes
Spotting tips, new species, and the best of what people are finding in the wild - straight to your inbox.