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Photo#225615
Sand wasp, but what kind?

Sand wasp, but what kind?
James Dilley Greenbelt Preserve, Laguna Beach, Orange County, California, USA
September 15, 2008
Pattern on abdomen seems really unusual. Behavior was different, as well. Instead of working the sand, this one was hovering in fairly tall flowers, then alit on a small stone.

Moved
Moved from Bembicina.

Not an ID, Ron,
but this looks like the abdominal pattern on male Glenostictia bituberculata. However, there are other characters to consider (i.e.if Steniolia, whether labrum is strongly bulging toward base, & with very long galea.) Bembicina for sure.
Good view of Steniolia mouthparts: #211651.

 
A question for anyone
How important are thorax markings here? This one is almost identical to several Steniolia, but very different from Glenostictia, at least in the images we have at Bug Guide.

 
That would make it easier
But, markings on the thorax don't figure in the generic key.

 
Ah, there's the rub.
Tony Thomas foresaw "Flies through a lens", whereby keying could be done from photos instead of specimen-in-hand techniques. To achieve that, we'll need new keys and likely a new vocabulary to go along with them. I'm hoping he's right, but doubt I'll be here to enjoy that golden time.

 
Hypothetically this might work
in many cases with photos that cover all of the diagnostically critical aspects of whatever group of insects you're trying to identify.
A frontal of this wasp, showing the mouth parts would most likely clear up whether this belongs in Steniolia. By the way, for both male & female Steniolia: "Labrum bulging ['strongly' in males] toward base, galea more than 2X as long as labrum" (Bohart and Gillaspy, 1985; reference on INFO page)
A recent experience identifying a robber fly (see here), with the help of Jim Hogue, made it clear that an ID using photography would be possible only by photographing the genitalia. For this you need very good magnification, and of course the specimen in hand.

 
Excellent explanation.
Most likely a Steniolia, but can't rule out Glenostictia, as the abdominal patterns are nearly identical. I believe the mouthparts of male Steniolia are very long, while those of females are shorter. Also, male bembicines tend to be larger than the females.

 
Thanks, Hartmut.
I saw another post with what appeared to be the same pattern, but no ID to Steniolia. Guess Bembicina is the place for this one.

check Steniolia

 
I wondered about that.
I've shot a fair amount of Steniolia, but felt the pattern on the abdomen was different on this one. The thorax, however, is almost dead on.

Do you think I'm being overly restrictive in my definition? (Happens from time to time.)

 
i'm no wasp expert -- only their humble fan :)
just can't help browsing leisurely... every now and then -- esp. when there are no funny new beetle posts on the Guide :-]

 
Thanks for any help you're willing to provide.
I'm alert to what you're doing, and have seen you help many people, including me. I'll keep looking for funny beetles, but have found precious few lately, even of the serious variety. (BTW, I suspect you're right on the wasp.)

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