O. arnoldii was first described from Tarragona, Spain by Delforge in 1999 and is named in honour of the contemporary botanist, Mr J. P. Arnold. This species is a member of the O. funerea group of Ophrys. There is however little consensus amongst experts as to the true status of the species and its become the subject of ongoing study in an attempt to establish its taxonomic position, particularly its relationship to O. lupercalis and O. forestieri  which many believe to be synonymous anyway. The confusion and doubts about its status as a species are not in any way allayed by the fact that all three of these Ophrys are pollinated by the same mining bee, Andrena nigroaenea.

This is another Pseeudophrys for which a description of morphological characteristics fails to satisfactorily distinguish it from  other similar species. Fowering periods can be of some guidance as O. arnoldii is the last of the three to bloom, first  appearing in mid April and sometimes persisting through to mid June. This later flowering enables it to avail itself of the services of the second generation of its pollinator.

O. arnoldii will tolerate a range of conditions from full sun to mid shade and dry to moist soils, though always on calcareous substrates. It is a robust plant with flowers that are large and often numerous (up to ten) with lateral lobes that although separated from the median lobe by significant sinuses, are invariably folded under in a way that usually disguises this feature.

The pictures are from northern Spain, southern France and Mallorca, dating from the last week in April, at which time the plants were just beginning their flowerng cycle.