Rayment's Red Bee

Description:

About 1 cm long. Dark upper body with reddish abdomen

Habitat:

I noticed these insects congregating together on a hanging branch of a tree in my garden last night. I believe they are a type of native bee, but can't be sure. I had a suggestion that they might be "Flame Tailed Resin Bees", but upon following up the antennae is different. I checked again a short while ago and they are back again in the same spot, but not quite as many as last night.

Notes:

This is a very similar thing done by the male "Green and Gold Nomia Bees" at night, which still remains a mystery as to why. If anyone can ID these insects I would be grateful