Compare the brown antenna:

I've posted a lot (hopefully not excessive) amounts of photos but not without reason. I had hoped someone would comment about the clustering behavior. I guess I should have just asked. Then secondly I wanted to try to determine if one color were male, and one female. Again, I could have just asked but I wanted to show the relevant parts so I could compare. The problem so far is that I have much better photos of the grays, and so I can only suspect. It seems almost certain that the ones clustered together would be the same species. The color and size differences seem to be real. Even the antenna color is different but it's not super obvious because the dorsal side of the antenna is dark on both, but the ventral sides, which are harder to see seem to be red on the grays, and brown on the golds. The base of the antennas on the grays is bright yellow, and seems to be just slightly yellow on the golds. Then antennas on the golds seem slightly shorter. So I am only guessing at this point that the golds are female.

...Looking through the photos of Female Melissodes that have been positively ID'd as such the hind legs are very bushy even if not loaded with pollen. The thing is...these males have pretty hairy legs. In fact they are pretty hairy all over. But its really hard to see much difference. Females obviously nest in the ground, but does that mean all the time or only when procreating? It seems like the males stay on flowers over night. A practice that you would think would leave them vulnerable to predators, but I guess my mission should be to find a female loaded with pollen during the day, although, most likely it will be coming and going, and not making picture taking very easy!