black-winged long-horned beetle

not listed

NNR - Unranked

not listed

Black-winged long-horned beetle is a small flower longhorn beetle, ¼″ to 7 ⁄16″ in length. The overall coloration is highly variable, making identification difficult.

The head may be entirely black, orange with a black stripe between the eyes, or entirely orange. The compound eyes are always black. The face slants forward or is nearly vertical. The antennae are long, black, thread-like, and at least half as long as the body. The base of each antenna is not surrounded by the compound eye.

The upper thoracic shield (pronotum) is bell-shaped, narrow at the front, widest at the base. It may be entirely black, orange with two small or large black spots, or entirely orange with no black markings.

The hardened wing covers (elytra) taper evenly from the base to the blunt tip, making the body appear broad-shouldered. They may be all black or black with a pale longitudinal stripe from the shoulder to the tip and a pale stripe at the inner margin where the elytra meet. The stripes may be narrow and well-defined, broad and diffuse and almost completely obscuring the black background, or anywhere in between these two extremes.

On each leg the third and largest segment (femur) is orange with black at the tip and the base. The fourth segment (tibia) is black. The last part of each leg (tarsus), corresponding to the foot, is black. The tarsus has five segments but the fourth segment is minute and is concealed within the lobes of the heart-shaped third segment, making it appear that there are only four segments.

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Until recently, this species name was considered a synonym of Brachysomida bivittata. In 2017 it was raised to a separate species. Neither a key nor a technical description of Brachysomida nigripennis was available at the time of this writing. The description above is of Brachysomida bivittata.

Total length: ¼″ to 7 ⁄16″

April to July

Nectar and/or pollen of flowers

Sources

24, 29, 30, 82.

Superfamily
A mitochondrial DNA and phylogenetic analysis of Cerambycidae and related families in the superfamily Chrysomeloidea was published in 2020. It showed that Cerambycidae evolved before Chrysomeloidea, and therefore should be placed in its own superfamily Cerambycoidea. However, there is no evidence that the resulting family would be composed of a common ancestor and all of its lineal descendants (monophyletic). For that reason the move has not been widely accepted. iNaturalist accepted the move. ITIS, NCBI, and BugGuide did not.

Species
Until recently, this species name was considered a synonym of Brachysomida bivittata. In 2017 it was raised to a separate species.

black-winged long-horned beetle

Brachysomida nigripennis Flower longhorn beetle

Brachysomida nigripennis, flower longhorn beetles on Golden Alexander flowers. Photos were taken May 30, 2022 at Barnes Prairie, Racine Co., WI.

… two pictures of the subject beetle. The same species, one black …

… and the other with black and rust colored stripes.

Location: Barnes Prairie, Racine Co., WI

Brachysomida nigripennis, flower longhorn beetles on Golden Alexander flowers. Photos were taken May 30, 2022 at Barnes Prairie, Racine Co., WI.

Location: Woodbury, MN