• Family: Colletidae
• Tribe: Colletini
• Approximate # species in region: 20
• Common name: cellophane bees, polyester bees, silk bees

Colletes are small to medium-sized bees with strong abdominal banding are more often found as singletons on flowers than other genera. They are named for the thin cellophane-like lining that they use to line brood cells. All Colletes nest in the ground. Some species are common and field identifiable, whereas others are rare and poorly understood.

In spring, there are three relatively common and conspicuous species, all of which can form big nesting aggregations and are field identifiable. In summer, there are many species, one of which is common on garden tomatillos, and others which are practically unknown to science. In fall, there are two common medium-sized species and a handful of smaller, compact species, which we are still learning to differentiate in the field. Summer and fall species are parasitized by bees in the cleptoparasitic genus Epeolus.

Distinguishing Colletes from Andrena is challenging for many beginning bee watchers. Notably, Colletes have convergent eye margins whereas Andrena have parallel eye margins (see below). In the net, Colletes often have a sweet lemon scent, unlike superficially similar Andrena.

Species covered: