Head: Eyes reddish-brown. Face front and top of head with white pile.
Antenna: Joints 1 and 2 dark, last joint yellowish to light brown, as long as 1st and 2nd combined.
Thorax: Black with lead gray sheen (plumbeous tinge).
Wings: Clear, with dark tinge (not dark enough to appear as a stripe) across center of wing, sometimes with wings closed, the tinge appears triangular. Another fainter dark tinge at tip, may not be visible.
Legs: Very long, mostly dark; thighs (femora) are variable. Shins (tibiae) and feet dark, except last 2 segments of front feet white and 2nd last segment of hind feet white (sometimes), toes dark. Front thighs (femora) pale yellow or entirely dark. Middle and hind thigh black with yellow base and yellow stripe just before tip or sometimes the black areas are more yellowish. R. antennaepes has more yellow on legs. R. a. brunneipes subspecies has darker legs.
Abdomen: Shiny black, underside paler. Males have claspers on underside of abdomen tip. Females have long ovipositor, sometimes protruding, but usually curled under abdomen tip.
Similar Species: Taeniaptera trivittata has only last segment of front foot with white, R. antennaepes has 2 segments white. T. trivittata has dark wings, especially at tips, with a narrow white stripe before, R. antennaepes has faded brownish tip, and a much wider ‘white’ area before tip.
Size: 7 to 9 mm.
Habitat: Forests and adjacent open areas.
Food: Dung, rotting vegetation, possibly rotting bark.
Flight Time: June to September.
Life Cycle: Larvae and pupa have been found in tree holes of deciduous trees. Pupa are formed side by side in rows of up to a hundred individuals and up to 38 of them per square inch. Adults emerge the first week of June. Rest of life cycle unknown. Assumed at least a second generation because they are here until September.
Comments: Essex County – Point Pelee, Lake Erie Island, Ojibway Prairies. Kent County – Rondeau Provincial Park. Widespread in southern and central Ontario.
For information on synonyms, references and type specimens see next page