Historically, Hylaeus facilis was known from Maui, Lanai, Molokai, and Oahu, in dry shrubland to wet forest from sea level to 3,000 ft (1,000 m) All Hylaeus bees roughly resemble small wasps in appearance; however, Hylaeus bees have plumose (branched) hairs on the body that are longest on the sides of the thorax, which readily distinguish them from wasps (Michener 2000, in litt.). Males of most of the Hylaeus species and females of several species have yellow marks on their face, hence the common name “yellow-faced bees.” Yellow-faced bees, in general, lack the elongated hairs on the hind legs that other bee genera use to carry pollen externally. The lack of these hairs gives them a wasp-like appearance. But, yellow-faced bees can be distinguished from wasps by the presence of branched hairs on the body that are longest on the sides of the thorax (Michener 2000, entire). Easy yellow-faced bee is a medium sized bee relative to other coastal Hylaeus species in the family Colletidae and subfamily Hylaeinae. The species has smoky colored wings. The male has an oval yellow mark on its face that covers the entire clypeus (lower face region), and a narrow stripe beside the eyes, but is otherwise unmarked. The large, externally visible gonoforceps (paired lateral outer parts of the male genitalia) distinguish the easy yellow-faced bee from the closely related Hylaeus simplex (Daly and Magnacca 2003, p. 83). The female is entirely black and indistinguishable from females of Hylaeus difficilis and Hylaeus simplex (Daly and Magnacca 2003, pp. 81–82). A more detailed description of the species can be found in Daly and Magnacca (2003, pp. 81–83). Bees in the family Colletidae are also referred to as plasterer bees because they line their nests with a self-secreted, cellophane- like material. Eggs hatch and develop into larvae (immature stage) and as larvae grow, they molt through three successive stages (instars), then change into pupae (a resting form) in which they metamorphose and emerge as adults (Michener 2000, in litt.). The diet of the larval stages is unknown, although it is presumed the larvae feed on stores of pollen and nectar collected and deposited in the nest by the adult female.