Hylaeus bacillarius, or Hylaeus (Heterapoides) bacillarius, is a species of bee in the family Colletidae and subfamily Hylaeinae. It is endemic to Australia. It was described by British-American entomologist Theodore Dru Alison Cockerell in 1914.
Description Male body length is about 4 mm. Integumental colouration is mainly black, with yellow markings.
Distribution and habitat The species occurs in eastern Australia. The type locality is Brisbane.
Behaviour The adults are flying mellivores. Flowering plants visited by the bees include Daviesia, Jacksonia, Leptospermum, Melaleuca and Tristaniopsis species.
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