Ptiloglossa is a small American genus within the bee family Colletidae

Colletidae

Colletidae is a family of bees, and are often referred to collectively as plasterer bees or polyester bees, due to the method of smoothing the walls of their nest cells with secretions applied with their mouthparts; these secretions dry into a cellophane-like lining...

, consisting of generally large, hairy species which are temporally-specialized crepuscular

Crepuscular

Crepuscular animals are those that are active primarily during twilight, that is during dawn and dusk. The word is derived from the Latin word crepusculum, meaning "twilight." Crepuscular is, thus, in contrast with diurnal and nocturnal behavior. Crepuscular animals may also be active on a bright...

 pollinators (active only at sundown, or vespertine

Vespertine

Vespertine, is the fifth studio album by the Icelandic recording artist Björk, released on 27 August 2001. On this album, Björk creates a quiet, introverted world of microbeats and personal lyrics...

, or more typically, at pre-dawn, or matinal), and they often utilize a pollen-extraction behavior known as buzz pollination

Buzz pollination

Sonication or buzz pollination is a technique used by some bees to release pollen which is more or less firmly held by the anthers, which makes pollination more efficient. The anther of buzz-pollinated species of plants is typically tubular, with an opening at only one end, and the pollen is inside...

. They have greatly enlarged ocelli

Ocellus

A simple eye refers to a type of eye design or optical arrangement that contains a single lens which detect light. A "simple eye" is so-called in distinction from a multi-lensed "compound eye", and is not necessarily at all simple in the usual sense of the word...

 to assist them in flying under very low light levels. They are most diverse in South

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 and Central America

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

 (30 or more species), with at least one species, Ptiloglossa arizonensis, occurring in the US. Like most colletids, these bees have liquid larval provisions sealed inside a membranous, cellophane-like cell lining, and it is believed that yeast

Yeast

Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...

s in the liquid may act as the primary protein source.