Switzerland, July 2006

Male, Switzerland, July 2006

The same male, just barely showing the red in the costal marks of the forewing

Female, showing prominent red

The same female

There has been much confusion recently about the scientific name of this species. The specific name by which it had long been known, phoebus, was shown by Hanus & Thèye in 2010 to rest upon misidentification of the original material, which actually belonged to a different species, later named Parnassius ariadne. The next-oldest available name, corybas, was therefore proposed and accepted. Thus, authors such as Leraut, 2016, treated the small Apollo across its range Parnassius corybas and our alpine populations in particular, Parnassius corybas sacerdos. Others, following Shepard & Manley (1998), restricted the name corybas to the Asian populations and raised the alpine populations to the level of good species, Parnassius sacerdos. Nevertheless, despite these differences of interpretation, everyone accepted after 2010 that phoebus could no longer stand. Then, in 2023, the ICZN ruled in its Opinion 3767, that the name phoebus should be conserved, for the sake of clarity and prevailing usage. After a decade of calling the butterfly corybas, I have therefore decided to revert to the old, familar phoebus. There seems no strong reason to recognise the alpine subspecies, sacerdos, as a good species, so it is properly called Parnassius phoebus sacerdos.

Whatever its name, the butterfly itself is a well defined taxon and relatively easy to identify. The male is strikingly white compared to a male Apollo (the black spot near the trailing edge of the forewing being absent or greatly reduced) and has a small amount of red in the postdiscal costal markings. The female has a substantial amount of red there. Another useful feature is the antennae, which are striped black and white/grey in this species but much more uniformly grey in the Apollo.

The small Apollo is more local than the Apollo but widely distributed in the Alps. I come across it less often and have yet to get a really good series of photos.