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Large Black Wasp - Chalybion californicum

Large Black Wasp - Chalybion californicum
Sunnyvale, Santa Clara County, California, USA
June 19, 2007
Size: approximately 20mm

Images of this individual: tag all
Large Black Wasp - Chalybion californicum Blue Mud Dauber - Chalybion californicum - female

Black Wasps seen in Tacoma Wa
I was stung by one of these bad boys two weeks ago in Tacoma Wa. They are extremely aggressive bees so be extremely cautious around them. Unfortunately I discovered a nest close to the size of a basketball in a small tree on my friends property. Most painful bee sting I have ever experienced in my life. Judging by the previous posts that I have been reading these bees are definitely on the move be careful near them.

These make mud nests...
I wonder what kind of bee or wasp it was. I have seen comparisons of sting pain, which, I suppose is subjective. I find bee stings to be the worst, and the common garden variety honey bee is the worst sting I have gotten. Ironically, the aggressive yellow jacket's sting is not nearly as painful to me. A mud dauber sting falls in between. I have never been stung by a black bee, but their size, and the fact that they are bees combined with their great size would make me wonder if they might not be some of the worst stings out their. I have never been bothered by them, but around their nest I imagine they could be very touchy.

Large Black Wasp - Chalybion
I just saw this wasp yesterday in El Dorado Hills, Calfornia, July 16, 2012. Big huge (~3 inches) black wasp looking for a place to build a nest. Nope, not catching him.

Large Black Wasp
I think this was the same wasp type that I just saw in Downtown Sacramento, California this past week on Sat, August 4th 2012.

Vancouver WA
This has invaded my backyard-Vancouver WA. It's new to me and I've lived here eleven years; I had to look it up. These things are mean :/

Not that mean!
I had a hard time getting close enough to get pictures...and besides, they kill spiders!


I can't get an ID since the w
I can't get an ID since the wings are covering most of the propodeum. I've seen a few sources saying that Chlorion is not recorded for California. The furthest west for the genus is Texas and Colorado. These sources might not be accurate now since they are a bit dated but should be kept in mind (if Chlorion is in CA, lemme know).

I emailed an authority and he said to check the dorsum of the propodeum. If you want, you can catch one, chill it, and spread the wings away from the thorax and get a photo of the propodeum (a good macro shot of the top of the thorax should be good). Hopefully I can tell what it is then.

Chlorion aerarium is known from CA

Yes, I see your point...
It really can not be stated to be Chalybion californicum from just this photo. There are some structural features that do differentiate them, as I am sure you know. By following this one for long time, I a was able to see a view of the face that is diagnostic. It's too bad I was not able to get a good shot of the face, but it had similar antenna placement as this one by Perry Babin:

If you can get it, a good sho
If you can get it, a good shot of the face would be useful too.

George, a new picture posted, does it help...
...I should not post the picture here, in this thread because, being seen on a different day, it could of course be a completely different insect. But it does look remarkably familiar so I will link to it, and if you follow the link you can keep up with the latest on this difficult ID! Your help is appreciated!


Chlorion in California
See my Bug Guide post:

There are also two posts from Arizona. If interested, see pages 67744 and 93735.

(Info like this is found - usually easily - with the Data tab, then going to Images and using Recent Images to go through the posts.)

Thanks for the heads up Ron,
Thanks for the heads up Ron, the references I used are definitely out of date.

Blue Mud Wasp?
If so, the first recorded from California, despite the scientific name (Chalybion californicum).

See also:

Ron, Could you elaborate on first recorded in California?
Do you mean with the guide, or for the year, or ever? And is it easy to look up distribution of species information? I'm new at this, but obviously distribution information could normally help a person with identification. This wasp appears to be a regular visitor. I've got more pictures that I am about to look at. Maybe I'll have something useful to upload.

Sorry I wasn't clear, part II.
I meant for Bug Guide. No entomologist, I'm not sure where to get distribution info except for butterflies, and I'm told my source isn't current. Bummer. That said, there are a lot of lists out there.

Sometimes the more common insects are the least reported. Don't know if you're familiar with the Data tab, but it shows in which states and on which months a given insect has been posted. The idea is to fill in all the relevant blanks (with decent or better images) so we all know distribution by time and place.

Thanks, yes- I've seen the data tab.
I have some pending questions about using the guide, though, but have been busy sorting my pictures in my spare time. I have many, many pending pictures to post. One group of pictures I have yet to post may increase speculation that this insect is NOT Chalybion californicum. Reason being, it looks somewhat similar, but has a lot of hair near the neck. I spotted it about five blocks away. They don't look like the same species to me, but I was hampered by a picket fence, and did not get very good shots. I hate posting pictures that aren't very good, but still, if it gets identified, I will help me learn this group better.

Thanks for all of your comments!
I certainly don't want to attempt an ID - I'm not even certain that the two wasps that Ron Hemberger linked to are the same, though they are extremely close.

Sorry I wasn't more clear.
They aren't the same. We have some good wasp people. Hopefully one or more will comment.

You were pretty clear, I was just checking...
When I saw they looked so similar I began to wonder, that's all. The first one looks the most similar to the one in my pictures to me, but the second one is almost a dead ringer for it too. I'll post another picture, though it may not help.

Steel blue cricket killer?
Could this be a steel blue cricket killer?

Head on the other two shots
There's just something about the head in the other two shots that reminds me more of Chlorion rather than Chalybion. If guesses are the best we can manage, though, I guess we'll have to just wait for someone more knowledgeable (it looks like I have more guesses than everyone else:-)

Might be right.
I am leaning toward Chlorion aerarium also. This specimen is likely a male if that is the case. Generally, Chalybion are slimmer, and obviously hairy on the face and thorax. This specimen looks quite devoid of hair, but still fresh (so no hair would have worn off in the course of its life). I'd still like to see what John Ascher has to say, and WaspGeorge as well.

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