North of Lobecks Pass, Southeastern Sacramento Mountains, San Bernardino County, California, USA
March 27, 2013
This bee fly was found torpid in a flower head of
Xylorhiza tortifolia, before the warmth of the morning sun energized it to begin the day's activities.
It keyed to
Lordotus in the MND
(1) and Cole
(2)...the wing venation is fairly distinctive. As far as trying for species, I don't have access to the 1954 or 1982
Lordotus treatments of Hall (see
info page), but images on BugGuide and in Lynn & Gene Monroe's recent book, "Desert Insects of Southern California & Kin"
(3), lead me to suspect that this is
L. pulchrissimus or
L. zona...and I'm leaning towards the former. Beyond genitalic differences, these two species are distinguished by the color of their coxae: yellow for
zona vs. black for
pulchrissimus. But the coxae are often not visible in photos, as is the case here. Cole
(2) commented that (green-colored emphasis below mine):
"L. zonus (sic) Coquillett is very common in certain areas of southern Calif.; it has also been taken in Ariz,, Nev., and Idaho. It is an autumn species in canyons of the San Bernardino Mts. of Calif. The wing is hyaline except for yellow in costal, sub-costal, and first basal cells."
On pg. 315 of Monroe
(3), it's said that female
L. zona are golden with white pile on the face, thorax, and femora and are active from August to November (at least in the southern California deserts), whereas
L. pulchrissimus lacks the conspicuous white patches on head and "chest", and is said to be active in spring as well as fall. As this bee fly was found in the spring; has no conspicuous white patches on face or sides of thorax; and has a more-or-less hyaline costal cell (as opposed yellow, as described for "
zonus" by Cole)...I'd tend to think this is probably
L. pulchrissimus.
And, perhaps the BugGuide posts below (with their autumn dates, white faces, and yellow costal cells) are
L. zona:
And the spring date and lack of white face on the post below might suggest
L. pulchrissimus, although the costal cell looks quite yellow to me:
Then again, perhaps wide "variation" makes these characters unreliable (and perhaps these two are just a single variable species?)...I don't know, just trying to understand.
One thing is for sure, this is definitely a female...from the widely separated eyes and the golden color (sexes are often dimorphic in color in
Lordotus, with males usually darker).