Males of P. pennina may be distinguished from males of other Pipizella species by their possession of a pair or shallow, denticulate projections close to the posterior margin of abdominal sternum 4 (Speight 2010).
Scratchpads developed and conceived by (alphabetical):
Ed Baker,
Katherine Bouton
Alice Heaton
Dimitris Koureas,
Laurence Livermore,
Dave Roberts,
Simon Rycroft,
Ben Scott,
Vince Smith