[2] Toxomerus basalis was first described in São Paulo and has collected in Rio de Janeiro, Santa Catarina, and Minas Gerais.

As with other Syrphidae species, the choice of egg-laying sites is critical for the survival of offspring and helps reduce interspecies competition.

The larvae are able to crawl freely and do not adhere to the Drosera mucilage because their bodies are covered by a thin layer of slime from salivary secretions.

Prior to pupation, the larvae release their gut contents and the bodies change to a dark brown color.

Toxomerus basalis is considered a true kleptoparasite because nutrients are not returned to the plant hosts - when the larvae release their gut contents, they are on the lower side of the leaf, which does not have any digestive glands.