Specimens of the New World genus Leschenaultia Robineau-Desvoidy (Diptera: Tachinidae) parasitise a wide range of lepidopteran hosts, including economically important pests. The female flies are attracted to volatile compounds released by host plants in response to the herbivory of caterpillars. They deposit microtype eggs on the leaves, which are then ingested by the hosts. We record a new host for L. bicolor (Macquart), obtained from Halysidota pearsoni Watson (Lepidoptera: Erebidae) in Ouro Preto, Minas Gerais, Brazil. The record is described herein and a comparative diagnosis for the identification of this parasitoid is provided, with discussion on similar species of the genus. The male and female terminalia of L. bicolor are fully described and illustrated for the first time. We also review and update the host records for Leschenaultia in an annotated host catalogue. At least nine species of Leschenaultia are recorded from 53 species of Lepidoptera, including the families Apatelodidae, Erebidae, Lasiocampidae, Noctuidae, Nymphalidae, Saturniidae, and Sphingidae. Finally, we provide an overview of host use and host associations.