The Rhagionidae or Snipeflies of the Botanical Garden Jean Massart (Brussels-Capital Region, Belgium) with notes on the identity of the rare European species Archicera avarorum Szilády, 1934 and Ptiolina obscura (Fallén, 1814) (Diptera: Rhagionidae) Author Grootaert, Patrick O. D. Taxonomy and Phylogeny-Entomology, Royal Belgian Institute of Natural Sciences, Brussels, Vautier Street 29, B- 1000 Brussels. pgrootaert@yahoo.co.uk Author Raemdonck, Hugo O. D. Taxonomy and Phylogeny-Entomology, Royal Belgian Institute of Natural Sciences, Brussels, Vautier Street 29, B- 1000 Brussels. Author O. D., Alain Drumont O. D. Taxonomy and Phylogeny-Entomology, Royal Belgian Institute of Natural Sciences, Brussels, Vautier Street 29, B- 1000 Brussels. text Belgian Journal of Entomology 2020 2020-09-17 104 1 18 journal article 10.5281/zenodo.13588506 2295-0214 13588506 08799CEE-C597-4D1C-90F2-569C42E9FAEB Archicera avarorum Szilády, 1934 ( Figs 3–5 ) MATERIAL EXAMINED : Belgium , Brussels-Capital Region : Auderghem , Jardin botanique Jean Massart , 2 females , 21–28 May 2015 , MT2 ; 1 female , 13–21 May 2015 , MT1 . ADDITIONAL OBSERVATIONS : 2 females , 11–17 May 2017 , MT6 ; 5 females , 11–17 May 2017 , MT2 ; 1 female , 11–17 May 2017 , MT5 ; 2 females , 17–24 May 2017 , MT2 (leg. A. Drumont & H. Raemdonck ) . Fig. 3. Archicera avarorum Szilády, 1934 . Female habitus. © Patrick Grootaert. COMMENTS A few more specimens of this very rare species were found in the year following the first sampling at the Garden, and thus examined and incorporated in the study. At first this species was confused with Spania nigra Meigen, 1830 . However, in S. nigra the flagellomere or third antennal segment has a rectangular base and bears a much thinner “arista” -like projection at the ventral corner of its apex. In all 13 females examined from the Garden, the entire flagellomere is broad throughout ( Fig. 3 ), also with a rather square base and no other segmentation is visible on the flagellomere. Such morphology of the antenna is typical for Archicera avarorum , a species and genus described by SZILÁDY (1934) on the base of two females . One female was found in Jasenak ( Croatia ) and another in Spital ( Styria , Steirermark, Oberösterreich , Austria ). It was originally described as a subgenus of Ptiolina and only later considered as a distinct genus. Eventually the genus Archicera was considered as a synonym of Spania by NAGATOMI (1982) and by KERR (2010) because the shape of the third antennal segment fell into the variability of Spania species. Since the two syntypes of A. avarorum were destroyed, PAPP (2018) designated a female recently found in Romania as neotype . PAPP did not wish to express himself on the status of Archicera and we follow his view and leave the question unanswered. His re-description fits entirely to our specimens and that is why we consider our specimens to be conspecific with A. avarorum . A. avarorum is a variable species. The shape of the flagellomere is slightly variable even on the same specimen ( Fig. 4 ) but it is always broad and flattened. The discal cell has 3 veins on its apex. The third vein generally does not reach the wing margin, which is a generic character for both Spania and Archicera . However, we found a specimen in which the third vein reaches the wing margin in one wing ( Fig. 3 ) but not on the other wing. In another specimen the discal cell was apically open while there was also a specimen in which the two apical veins of the discal cell arose from the tip of the discal cell in one wing as was illustrated by PAPP (2018) in a Spania specimen. Fig. 4. Archicera avarorum Szilády, 1934 . Female: A. Antenna of left side; B. Antenna of right side of same specimen. Scale: 0.1 mm. © Patrick Grootaert. The palp consists apparently of a single segment as no separation of palpomeres was visible ( Fig. 5D ) The palp is broad with a truncate tip, bearing two small bristles at the tip and a series of long bristles dorsally at the base ( Fig. 5D ). The proboscis is tubiform and the labellae are large. The pseudotracheae are thin, long and coiled and some might be furcate so that it is not clear if 8 or 9 pseudotracheae are present ( Fig. 5D, E ). Fig. 5A illustrates the female terminalia in dorsal position while Fig. 5B shows the ventral position.