Fulminating long-horned beetle

Conservation Status

IUCN Red List

not listed

NatureServe

NNR - Unranked

Minnesota

not listed

Description

Fulminating long-horned beetle is a medium-sized, early season, round-necked longhorn beetle. It occurs in the United States from Maine to Maryland, west to Minnesota and Missouri, and south along the Appalachian Mountains to North Carolina. It also occurs in southern Canada in Quebec, Ontario, and Manitoba.

Adults are active from May to July, with peak activity occurring in June. The larvae are found under the bark and in the sapwood of hardwood trees, especially chestnut, oak, and walnut.

Adults are ½″ to ⅞″ (12.0 to 22.0 mm) in length. The body is nearly cylindrical and significantly elongated. It is entirely black with patterns of dense white hairs.

The head is slightly elongated. The eyes are deeply notched, partially surrounding the base of each antenna. The antennae are long, reaching at least the second third of the wing covers (elytra). The bases of the antennae are closely spaced. The face is slanted forward. The plate on the face (clypeus) is well developed.

The plate covering the first segment of the thorax (pronotum) is oblong, almost spherical. Dense white hairs form a distinctive, large, black spot in the middle and a distinct, smaller black eyespot on each side. On the underside of the third segment of the thorax, a plate on each side (metepimeron) is four times longer than wide, and it extends over the rear angles of the first segment.

The elytra are parallel sided, and they are cut off (truncated) in the rear, exposing the last segment of the abdomen. Dense white hairs form five narrow, sharply angled, transverse bands crossing both elytra.

The legs are long. On each leg, the third segment (femur) is gradually thickened toward the end. The last part of each leg (tarsus), corresponding to the foot, has five segments. The fourth segment is very short and is concealed within the broadened tip of the third segment, making the tarsus appear to have only four segments.

Size

Total length: ½″ to ⅞″ (12.0 to 22.0 mm)

Similar Species

Habitat

Ecology

Season

May to June

Behavior

Adults will come to light and to baited traps.

Life Cycle

Larva Food/Hosts

Adult Food

Distribution

Sources

24, 27, 30, 82, 83.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu. Accessed 6/6/2026).

Sarosesthes fulminans (Fabricius, 1775) in GBIF Secretariat (2023). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org. Accessed 6/6/2026.