Hylemyia caesia, Macquart, 1835

Pont, Adrian C., 2012, Muscoidea (Fanniidae, Anthomyiidae, Muscidae) described by P. J. M. Macquart (Insecta, Diptera), Zoosystema 34 (1), pp. 39-111 : 54

caesia Macquart, 1835 , Spilogaster

Spilogaster caesia Macquart, 1835: 296 . Syntype (s) ♂ (♂), “du nord de la France ” ( France, Lille area), not in MNHN or MHNL, and presumed destroyed.

MATERIAL. — Described from an unspecified number of ♂♂. No syntypes have been located. There is 1 ♂ in MNHN labelled by Macquart as “N°. 81. / Spilogaster / caesia.”. This is a species of Helina Robineau-Desvoidy, 1830 , but does not agree with his description of this species.

CURRENT IDENTITY. — The name caesia was widely used in the 19th century for the species now known as Helina confinis (Fallén, 1825) (syn: anceps (Zetterstedt, 1838)), but both Bezzi & Stein (1907: 635) and Hennig (1957: 159) showed some hesitation in synonymizing true caesia with this species. In my opinion, Macquart’s description of caesia refers to the common European species Helina reversio (Harris, 1780) (syn: duplicata (Meigen, 1826)) , and this synonymy has been published ( Pont 1986b: 149). The species described by Macquart as duplicata a few lines before caesia has “pieds noirs” and cannot therefore be reversio . However, in his description of caesia, Macquart mentions “pieds noirs; jambes quelquefois d’un testacé noirâtre”, which fits reversio exactly.