Key to the species of Perdita subgenus Perditella.
Note: Care must be taken when identifying specimens because important features, particularly the pygidial plate, can often be slightly misshapen, presumably due to the weak sclerotization of these minute bees.
Species not included in the key: P. minuta, P. pusillissima -- these are not valid species.
1. Males: 13 antennal segments; clypeus generally strongly dentate on each side of labrum; 2nd medial cell absent.....2
Females: 12 antennal segments, clypeus lacking strong dentation; 2nd medial cell present.....5
2. Wing venation light, body coloration mostly yellowish...3
Wing venation dark; body coloration brown or black....4
3. Dark maculations prominent around ocelli and dorsally on the thorax, dentation of clypeus with inner margin straight, not bowed outwards towards side of face; dentations extremely protruding in large-headed males…..P. marcialis
Dark maculations, if present, limited to a small area around ocelli, and two marks on the bottom of the mesepisternum; dentations on clypeus with the inner margin curved outward towards sides of face and length of dentations never exceeding width......P. larrea
4. Face white below antennae, dark above; thorax dark....P. cladothricis
Body uniformly splotchy brown-colored....P. minima
Females
5(1). Wing venation light/clear; scutum dark, tessellate, and quite dull...6
Wing venation dark, scutum shining, at most slightly tessellate....7
6. Pygidial plate triangular, with a narrow, barely rounded tip; coloration always dark......P. marcialis
Pygidial plate broadly rounded; coloration ranging from entirely light to entirely dark.....P. larrea
7. Scutum dark and shining, abdomen dark, with a (sometimes obscured) medial white band on T2; pygidial plate triangular with distinctly truncate apex......cladothricis
Body uniformly amber/splotchy brown; microsculpture on thorax tessellate and more or less dull; pygidial plate triangular with apex rounded......minima (Note: pygidial plate surprisingly variable, ranging from broadly rounded and spatulate to triangular with a rounded tip. The normal state of pygidial is a broadly rounded triangle with a slight upward-facing carina that rings the edge of the pygidial plate. However in some specimens the cuticle that forms the carina has remained appressed, resulting a more broadly rounded and spatulate pygidial plate. Not clear if this is a natural abnormality of a symptom of the bees’ flimsy cuticle drying out).
Note: Care must be taken when identifying specimens because important features, particularly the pygidial plate, can often be slightly misshapen, presumably due to the weak sclerotization of these minute bees.
Species not included in the key: P. minuta, P. pusillissima -- these are not valid species.
1. Males: 13 antennal segments; clypeus generally strongly dentate on each side of labrum; 2nd medial cell absent.....2
Females: 12 antennal segments, clypeus lacking strong dentation; 2nd medial cell present.....5
2. Wing venation light, body coloration mostly yellowish...3
Wing venation dark; body coloration brown or black....4
3. Dark maculations prominent around ocelli and dorsally on the thorax, dentation of clypeus with inner margin straight, not bowed outwards towards side of face; dentations extremely protruding in large-headed males…..P. marcialis
Dark maculations, if present, limited to a small area around ocelli, and two marks on the bottom of the mesepisternum; dentations on clypeus with the inner margin curved outward towards sides of face and length of dentations never exceeding width......P. larrea
4. Face white below antennae, dark above; thorax dark....P. cladothricis
Body uniformly splotchy brown-colored....P. minima
Females
5(1). Wing venation light/clear; scutum dark, tessellate, and quite dull...6
Wing venation dark, scutum shining, at most slightly tessellate....7
6. Pygidial plate triangular, with a narrow, barely rounded tip; coloration always dark......P. marcialis
Pygidial plate broadly rounded; coloration ranging from entirely light to entirely dark.....P. larrea
7. Scutum dark and shining, abdomen dark, with a (sometimes obscured) medial white band on T2; pygidial plate triangular with distinctly truncate apex......cladothricis
Body uniformly amber/splotchy brown; microsculpture on thorax tessellate and more or less dull; pygidial plate triangular with apex rounded......minima (Note: pygidial plate surprisingly variable, ranging from broadly rounded and spatulate to triangular with a rounded tip. The normal state of pygidial is a broadly rounded triangle with a slight upward-facing carina that rings the edge of the pygidial plate. However in some specimens the cuticle that forms the carina has remained appressed, resulting a more broadly rounded and spatulate pygidial plate. Not clear if this is a natural abnormality of a symptom of the bees’ flimsy cuticle drying out).