After running into John & Jane Balaban's Pepsis
...I was motivated to check my archives for any photos I might have taken of the same Pepsis
, so I might scour them for more diagnostic characters to work on an ID. Many of us participants at the 2013 AZ BugGuide gathering saw pepsines (and many
other taxa) visiting galls strangely laden with "nectar" (actually honeydew) on the oak tree
in front the station.
Fortunately, I was able to find some Pepsis
photos from those oak galls that...although not very good aesthetically...at least manage to show critical characters for obtaining an ID.
The individual I photographed was a male, as can be seen here from the more-or-less straight, relatively thickened antennae...and
the presence of dense, abdominal "hair brushes" on the distal sternites (see pink arrows on the full-size image
). Such "hair brushes" are only present on males of certain (not all) species of Pepsis
...in our (north of Mexico) area, those species include: angustimarginata, azteca, cerberus, elegans, mildei
, and saphirus
(I've used the "old names" here, see the Pepsis info page
for the current synonymies).
These "hair brushes" can provide useful characters for keying males of these species (in terms of various details involving their location, shape, positioning, relative length and curvature, etc.). In the individual here, it can be seen that there are virtually no
hair brushes on the 5th sternite (just short, inconspicuous hairs there); and two, short, inwardly-arched, longitudinal brushes positioned laterally near each edge of the 4th abdominal sternite...with their longish-hairs curl inward towards the central axis of the abdomen
. Other important characters for the ID here are the entirely black antennae; the predominantly orange wings, with narrow dark marginal bands (without
hyaline tips!); and the pronounced ("pointed") mesopleural tubercle (white arrows).
From the above-mentioned characters, this keys unambiguously to Pepsis "angustimarginata"
(1952). That name has been used for many decades in the literature focusing on nearctic species of Pepsis
...but it was recently synonymized under the name Pepsis basifusca
(2005), whose work focuses more on the neo-tropical area, where the great majority of Pepsis
species occur. The epithet "angustimarginata"
presumably refers to the (rather uniformly) narrow dark marginal borders of the fore and hind wings, which extend from near the tip of the marginal cell, around the apex of the wing, and continue along the posterior edge to near the axillary excision. Similarly, the epithet basifusca
presumably refers to the typically darkened base of the wings.
You can read Viereck's original 1907 description of a female P. angustimarginata here
; Banks has brief comments on males here