Cicada killers are huge wasps. They bury adult cicadas (not live cicada larvae) to feed their own young in underground nests. Harmless to humans and gardens, and very interesting creatures to watch.

Your ground is probably a bit sandy or easily dug when dry, yes?

If michaelg is correct (as I strongly suspect he is) then the insect you're seeing is this one: {{gwi:319654}}.

They're bigger than most wasps one encounters in the Northeast (with the possible exception of the bald faced hornets) and so they do look intimidating, but they totally ignore people, even as they dig in people's lawns making burrows for their young, which eat adult cicadas provided for them by those same adult wasps.

The best thing to do is ignore them, as they ignore you.

Most of the animal world around us goes on about its business completely unaware of and indifferent to our existence. If you let them be so they will be one of the best examples of this you will ever personally encounter. The annual "dog day" cicadas of high summer are at worst extremely minor pests, so cicada killers are likewise (for all practical purposes) irrelevant to us humans, even when we are gardeners.

For a while after I graduated from college I lived with my parents, and during that time, occasional lawn mowing and constant regular gardening included, that property had a front yard slope with a patch of ground used by cicada killers. None of the people in my family are allergic to bee stings (& I've been stung by other bees & wasps when I was an entomology grad. student collecting insects carelessly), but no one in my family (including me, and specifically including when I collected a cicada killer for my entomology grad. student-required insect collection) has ever been stung by a cicada killer.

For whatever reason in my personal experience they truly are utterly indifferent to our existence.

For the first time this year an insect has appeared which was completely unknown to us. We determined it (although it's actually they) to be a tarantula hawk. It's large and frightening looking. It kills tarantulas and lays its eggs on the body which will then feed the young. The worst part is that its sting is apparently the most excruciatingly painful that you could ever experience, far beyond anything another stinging insect can inflict. Naturally the subspecies we have here has the worst sting of all. Coming upon them daily at very close quarters for the last few weeks has been a little unsettling. And yet I can't bring myself to destroy them, assuming it could be done without getting stung. I'm hoping they'll move on really, really soon.

Ingrid

So Ingrid, do yo think I also have these tarantula hawks in my garden? I live on the east coast though...
Everyone's responses seem right. The pic york_rose posted is quite close to the original. They look scary, these cicada killers.
Anyway, should I just leave these burros untouched? The lawn looks bad, but if the insects aren't harmful...
Interesting enough it's the first year they are so abundant. I noticed them in previous years, but only occasionally. What may have caused them to settle in my front yard though? The only explanation is the weather which this year had been awful. I cant remember a similar summer. Every year we get a visit from Japanese Beetles, but this year they were quite absent. Instead, we have these wasps... Oh, well

Ingrid, that sounds terrible!! Is there really no service from the town/province/state health department to get rid of these insects? They sound really dangerous to people!!

From Wikipedia:
The sting, particularly of Pepsis formosa, is among the most painful of any insect, but the intense pain 'only' lasts for 3 minutes. Commenting on his own experience, one researcher described the pain as "Âimmediate, excruciating pain that simply shuts down one's ability to do anything, except, perhaps, scream. Mental discipline simply does not work in these situations." In terms of scale, the wasp's sting is rated near the top of the Schmidt Sting Pain Index, second only to that of the bullet ant and is described by Schmidt as "blinding, fierce [and] shockingly electric".

Mike, for the cicada killers, leave the burrows alone. While they are not outright aggressive, they might chase you away from their burrows. I've heard they can be protective/territorial in that regard.

Eric

Scardan, if there were small children around I probably would do something but fortunately it seems that as long as you leave them alone they're not aggressive. The other day I unknowingly put my face within a foot of it as I was mulching and it didn't even move.

Mikeber, I definitely don't think you have this insect, yours has already been correctly identified, and seems completely harmless.

Ingrid

I would have an exterminator come out and spray the lawn. You can't have insects damaging your grass.

You could also blanket the area in malathion if you have the equipment.

spawish = troll

^ That's right, just trying to push people's buttons.

Cicada killers will aerate that patch of lawn for free, which you otherwise pay a landscaper to do.

No, they aren't tarantula hawks. Those are a specialty of the Desert Southwest. We don't even have their food source (tarantula spiders) in the Northeast.

Mikebar,

Is this what you saw?

[IMG]http://i898.photobucket.com/albums/ac185/Prairiefrost/cicada_killer_wasp.jpg[/IMG]

I had one of these baby show up two years ago while I was working in my lily garden. Nearly scared me to death. I'm use to bees and bumblebees but wasp bother me. I left it alone and it did the same with me. I thought it was gone this year but it showed up a couple of week ago. I had put some potted roses by garage so they could get some sun. One of these days I will get them in the ground. Anyway, it was flying really close to me so I froze and then backed away. It was only later that I realize that I had cover up it's entrance to it's home. Thanks for posting this, now I know what it is and I was right to leave it be.

Okay let me try this again.

{{gwi:319656}}

Nice pic of a cicada killer!