Random Invertebrate Day #1 Sweat Bees

Since I have a lot of pictures of invertebrates, I've decided to post some of them in a new feature, the Random Invertebrate Day. To be clear, it's the day that is random, not the invertebrate. The days have been selected using the random number generator on Google Docs, so I guess it's probably actually the Pseudorandom Invertebrate Day. There's a 1-in-7 chance of any day being selected.

For my first post I've got some pictures of sweat bees at the entrance to their nest, taken in Mazunte, Mexico.

Click on the photos to see a larger version