Extracted from 2017 “Bees of Maryland: A Field Guide” http://bio2.elmira.edu/fieldbio/beesofmarylandbookversion1.pdf
Tiny and uncommon. However in the right sandy habitats, with the right native
composites; particularly dune areas, sand mines, or other sparse areas of deep sand,
some sand Perdita species can occur in high numbers.
Field Marks: ♀♂Tiny size, body hairs very sparse (except for P. bequaerti,
which is only moderately hairy). Hairs never forming bands or dense enough to be
noticeable in the field. Wings, 2 submarginal cells. Face, usually, wider than long
(one rare exception). Wing, marginal cell super short (its length along the edge of
the wing is equal to or less than the length of the adjacent dark stigma) with the end
clearly squared off rather than pointed. ♀Integument black to slightly metallic blue
or green, almost always with some light-colored markings on face. Abdomen
markings vary from none to stripes, often forming small blotches on the sides.
Markings tending to be white to light yellow not bright yellow. Clypeus, scape
(large antennal segment next to head), and area to sides of clypeus almost always
with light-colored markings dissected by dark areas. Hind legs, pollen carrying
hairs, all species except P. bequaerti, sparse and hardly noticeable thus the females
often appear male-like. ♂Face below antennae, all or primarily white to light yellow
in most species. Face noticeably wider-than-long and squarish. Antennae short, not
noticeably longer than female.
Flight Season: Late summer/fall for sandy soil species
Size Relative to Honey Bee: 0.3 - 0.5X
Position of Wings Feeding on Flowers: Completely overlapping
Location of Pollen Carrying Hairs: Hind tibia and basitarsus
Similar Genera: Hylaeus - ♀Has yellow/white markings on face only
between eye and clypeus, carries no external pollen. ♂Entire lower face often
yellow/pale-white, but body dark black and legs with some yellow/white markings
on them. Calliopsis - Face, markings quite different, has pale hair bands on
abdomen. Panurginus - Flight periods do not overlap, spring species.
Pseudopanurgus - ♂Clypeus bright yellow. Body black. Legs with yellow
markings. Head less wide, less square. ♀Entirely dark black. Most of the Other
Genera that are Small Black Bees - 3 submarginal cells. Hair, patches/bands of pale
hair. ♂Longer antennae
Nest: Ground, open bare sandy soil
Flowers: Sand species are found on fall composites, two rare species are
found on Maleberry (Lyonia ligustrina) and False Foxglove (Agalinus spp.).
Notes: Two very rare species (P. gerardiae and P. novaeangliae) are not
associated with deep sand.