Two of the subfamilies, Euryglossinae and Hylaeinae, lack the external pollen-carrying apparatus (the scopa) that otherwise characterizes most bees, and instead carry the pollen in their crops.
In the context of bees, two subfamilies, Euryglossinae and Hylaeinae, exhibit an unusual characteristic by not possessing the usual scopa structure, and instead rely on their digestive systems to transport pollen.