Amphasia interstitialis
(Say, 1823)
Red-headed Ground Beetle
Amphasia interstitialis, commonly known as the red-headed ground beetle, is a small ground beetle native to North America. measure 8.5–10.2 mm and display distinctive coloration with dark contrasting against an orange pronotum and . The occupies moist, covered microhabitats within deciduous forests, including leaf litter and spaces beneath stones and logs. It is widespread across the northeastern United States and adjacent Canadian provinces, with extending into the central United States.
Identification
Distinguished from other ground beetles by the combination of orange and pronotum against dark . The 11-segmented and pale orange legs provide additional diagnostic characters. Similar-sized carabids with dark coloration typically lack this pronounced orange-dark contrast on the surface.
Images
Appearance
are 8.5–10.2 mm in length. The are dark, while the pronotum and are orange. have 11 segments and are lighter orange in color. Legs are pale orange. The underside of the is dark anteriorly, with the rear portion of the abdomen and remaining surface orange.
Habitat
Deciduous forests, particularly in moist, covered microhabitats such as leaf litter, under stones, and beneath logs. Also occurs in lowland wetlands and mesic areas.
Distribution
Northeastern United States, extending into Ontario and Quebec, Canada; also present in the central United States.
Similar Taxa
- Other Amphasia species members share ground beetle but differ in color pattern and distribution; specific comparisons require examination of pronotal and elytral coloration
- Small dark Carabidae with pale appendagesSize overlap and general ground beetle habitus; distinguished by the distinctive orange -pronotum contrast of A. interstitialis