Chrysops niger

The black deer fly can be distinguished from other Chrysops species by its predominantly black body coloration combined with black-barred wings. Many deer flies have yellow or orange markings on the body; C. niger lacks these. The wing pattern of dark bars is diagnostic within its range. Similar species with dark bodies typically show different wing patterns or body markings.

Adults measure 8–10.5 mm in length. The body is mostly black with scattered white hairs. Wings are transparent with distinct black bars. Sexual dimorphism in eye structure is typical for the genus, with males having holoptic eyes and females dichoptic eyes, though specific details for this species are not documented in available sources.

Associated with marshy areas and wetlands. Larvae inhabit damp soil with high water content.

Eastern United States and Canada. Specific records include Vermont.

Adults are active from May to September.

Adult females are blood-feeders; males and specific host associations for C. niger are not documented. Larvae feed on organic matter in damp soil.

Complete metamorphosis with egg, larva, pupa, and adult stages. Larvae are hydrobionts, inhabiting areas of high water content in damp soil where they feed on organic matter. Duration of developmental stages not documented for this species.

Adults are active diurnally during the flight season. Females bite humans and likely other mammals for blood meals, as is characteristic of the genus, though specific host records for C. niger are not documented. Adults are associated with marsh habitats.

Larvae contribute to decomposition in wetland soils. Adult females function as blood-feeding parasites of vertebrates. Specific ecological impacts not documented.

Adult females bite humans, causing painful welts. The species is a nuisance pest in marshy recreational areas during summer months. No documented disease transmission for this species, though deer flies in general can mechanically transmit some pathogens.

• Other Chrysops speciesMany deer flies have yellow or orange body markings and different wing patterns; C. niger is distinguished by its mostly black body with white hairs and black-barred wings

• biting fly
• deer fly
• marsh habitat
• pest
• Tabanidae

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
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