Purpuricenus humeralis

Distinguished from P. axillaris by triangular (not transverse) basal elytral markings that cover only the humeri rather than the basal half of the elytra, and by the posterior margin of the markings being oblique rather than more or less transverse. Differs from P. paraxillaris by weaker pronotal calluses without polished apical line on the median callus, smaller lateral pronotal tubercles with obtuse (not acute) angles, finer and sparser basal elytral punctation, and subtruncate (not emarginate) elytral apices without distinctly dentate angles. The elytral markings in P. humeralis are typically more reddish than the yellow-orange of P. axillaris.

Large, robust cerambycid beetle with velvety black integument. Basal elytral markings are distinctly triangular, covering only the humeri (shoulders), colored vivid red to orange-red. Posterior margin of these markings is oblique, with the apical dark area extending forward along the suture to reach the scutellum. Pronotum with weak discal calluses; median callus lacks a polished apical line. Lateral pronotal tubercles are small with obtuse angles. Elytral apices are subtruncate, with angles not distinctly dentate. Basal elytral punctation is relatively fine and sparse compared to congeners. Antennae are long, extending beyond the body in males.

Associated with forested habitats, particularly oak woodlands. The species has been collected in dry post oak woodland, xeric sand prairie remnants with oaks, and mesic lowland deciduous forest. Adults are attracted to fermenting bait traps placed in these environments. Larval hosts likely include oak species (Quercus), based on habitat associations and comparison with related species.

Northeastern North America, ranging from Canada (Manitoba, New Brunswick, Ontario, Québec) south and west to Oklahoma. Not currently recorded from Texas. The species occurs in the central and eastern United States, with collection records from Missouri, Illinois, and surrounding states.

Adults are active in summer, with collection records from mid-June through July. Peak activity appears to coincide with warm summer conditions. Attraction to fermenting bait traps suggests adults may be seeking food sources or oviposition sites during this period.

• Quercus - probable larval hostBased on habitat associations in oak woodlands and comparison with congeners; specific host records not documented in available sources

Adults are attracted to fermenting bait traps containing mixtures such as molasses, beer, yeast, and water. They are primarily nocturnal or crepuscular in their attraction to baits. The species appears to be a strong flier capable of locating bait sources from distance. Adults do not feed on wood; larvae are the wood-boring stage.

As larvae, likely function as wood-borers in oak and possibly other hardwood species, contributing to nutrient cycling in forest ecosystems. The specific ecological role is not well documented but is inferred from related species and family characteristics.

Of interest to coleopterists and naturalists due to its large size and striking coloration. The species was historically sought after by collectors using fermenting bait traps, contributing to early documentation of its distribution. Not known to be an economic pest.

• Purpuricenus axillarisSimilar size and coloration, but distinguished by transverse (not triangular) basal elytral markings covering the basal half of elytra, yellow to orange (not red) markings, and weaker pronotal features
• Purpuricenus paraxillarisSimilar appearance but distinguished by more robust build, prominent pronotal calluses with polished apical line, acute lateral pronotal tubercles, coarser elytral punctation, and emarginate elytral apices with dentate angles
• Purpuricenus linsleyiOccurs in Texas hill country and can be confused with P. humeralis, but has different elytral marking shape and is geographically separated

• longhorn beetle
• wood-borer
• fermenting bait
• oak-associated
• showy beetle
• eastern North America

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• A Silver Anniversary | Beetles In The Bush
• Mydidae | Beetles In The Bush
• August | 2022 | Beetles In The Bush