I, for one, would like a picture of black and red critters, and the gray ones. Are you absolutely certain that they are beetles and not of a similar insect order?

They were black and red earlier in the season and now some are grey and some are black. Maybe the black and red ones weren't the same thing as the grey or black. The had the same body shape and sure did like hanging out on the pumpkins. I'll run out and try to grab some pics. Thanks,Vicci

What, if any, damage are they doing to the plants. Are they pests or are they beneficial insects that need to be coddled?

I took the pics but my computer won't work properly. They seem to be making little holes in the pumpkins. At first I thought they were just sitting there but yesterday I cut my pumpkins from the vines and most were mushy on the bottom and almost had at least tiny holes in them. I have millions of these bugs in my garden. Mostly on and around the pumpkins but also on the tomatoes and in the soil. They do have a design to them. They are like solid grey when they are little to middle size. When they are grow they are a brown and black color, sort of have a V shape mark where the brown and black come together. My dad said they look like a stink bug. I pulled the rest of my tomato plants out yesterday and all the pumpkins and dead vines. These crazy bugs are everywhere. I didn't get bit by any of them so I guess they aren't biting bugs. Thanks for your help everyone. Vicci

O.K. looks like they must be stink bugs. There is nothing left in my garden now that will be eaten so is using sevin dust o.k.? Will it help. Next year this will be a flower garden will they still be as big a pain in the neck? Thank you again. Vicci

Using Sevin will almost guarantee they will be back. You will kill off the stink bugs but also the predators that help keep them under control. Once you use a chemical spray it is a never ending cycle. That's what keeps the chemical companies in business (and in your wallet)

I wonder if these were box elder beetles.

I have a large infestation of them and we have two female box elder trees in our yard.

Here is a link that might be useful: http://www.ext.colostate.edu/pubs/insect/05522.html