This is a sedum, or stonecrop, plant. On it there are 3 insects. On the bottom left there is a normal sized bumble bee. Bumble bees are pretty big already and this one is a good sized one. On the bottom right is an abnormally large bumble bee. I don't know how it got as big as it is, but if you know anything about the size of stonecrop, you might be able to tell that it's about an inch long. Which brings us to the wasp at the top. That wasp is about an inch and a half long. After these bees and wasps have drank of the sweet nectar, they go into a drunken rage and everyone steers clear.
I just thought you all might like to know about the danger that I live with every day as I slave away among the foliage of a retail rooftop.