Mosquito bee

These sting-less bees are one of the smallest in the world. About 4mm. They are also one of the greatest of pollinators of native plant species. They nest in fissures on the rocks or brick walls or even abandoned electrical conduits as shown here. On very hot weather I have seen worker bees fan the mouth of their entrance with beating wings. In the third photo they were seen repairing the entrance tube with fresh wax.