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REMAINING (number with state)
Abdomen, T2, in the center of the segment, average distance of one pit to the pit nearest it, excluding any bare rim - Measured in units of pit diameters
Less than 1 (27)
1 - 3 (26)
Greater than 3 (9)
No pits present (1)
Abdomen, T2, in the center of the segment, percent of unpitted region along the rim, measured in longitudinal distance
25 - 15 (21)
75 - 25 (18)
15 - 5 (15)
Abdomen, color
All black (24)
Tip of abdomen black, basal terga red (15)
T1 partly black, T2-3 red, T4-7 black (10)
All red, red can be dark or light (9)
Head, antenna, length compared to width of second flagellar segment
About as broad as long (17)
About 1.5 times longer than broad (15)
Broader than long (14)
Two or more time long as broad (11)
Head, antenna, length of first flagellar segment compared to length of second flagellar segment
F1 half or more the length of F2 (29)
F1 one third or less the length of F2 (8)
Head, antennae
Normal (27)
With facets (9)
Head, cheek, presence of a carina or minutely upturned ridge along the lower edge
Absent (32)
Present (3)
Head, presence of a very prominent elliptical mound directly behind the ocelli
Absent (31)
Present (2)
Problematic species for which only the types are known or whose identification is uncertain
RECOMMENDED - Drop these species from the list (36)
DISPLAY these species (5)
S. antennariae vs. S. autumnalis vs. S. brachycephalus
S. antennariae - Forewing, cell number, ALWAYS JUST 2 submarginal cells - Head, flagellar segments 7-9 clearly WIDER THAN LONG or, at most, approaching equally long as wide - Thorax, scutum, SLIGHTLY DEPRESSED SULCUS, or line, that runs like a shallow gully from the center of the anterior edge of the scutum about half way down, similar in width to the paropsidial lines - In comparison with S. brachycephalus, scutum sulcus is not as clear (1)
S. autumnalis - Forewing, cell number, usually has 3 submarginal cells - Head, flagellar segments 7-9 about AS LONG AS WIDE - Clypeus, clypeal hairs largely hiding the surface - Thorax, scutum, with a VERY FAINT CENTRAL LINE running from the anterior edge of the scutum to about half way down, or no line at all, but this area is not depressed below the surrounding surface or depressed area (1)
S. brachycephalus - Forewing, cell number, usually has 3 submarginal cells - Head, flagellar segments 7-9 clearly LONGER THAN WIDE - Clypeus, readily visible, hairs present but not so dense to hide surface - Thorax, scutum, a CLEAR DEPRESSED SULCUS, or line, runs like a shallow gully from the center of the anterior edge of the scutum about half way down, similar in width to the paropsidial lines (1)
S. aroniae vs. S. ranunculi
S. aroniae - Leg, middle femur, EXTREMELY WIDE, 2 or more times as wide as the widest point of the tibia, the angle formed by the lower edge almost 90 degrees - In comparison with S. ranunculi, the front coxae almost completely FLAT and WITHOUT HAIRS (1)
S. ranunculi - Leg, middle femur, VERY WIDE compared to other species besides S. aroniae, but only approximately 1.5 times as wide as the tibia, the angle formed by the lower edge approximately 130 degrees - In direct comparison, the front coxae are very SLIGHTLY ROUNDED and have SCATTERED HAIRS (1)
S. autumnalis vs. S. banksii
S. autumnalis - Abdomen, tergal pits, VERY FINE and quite DIFFICULT TO DETECT at 30X, but are present - Head, clypeus, hairs largely HIDING SURFACE - Difficult to separate from S. banksii (1)
S. banksii - Abdomen, tergal pits, FINE, but READILY VISIBLE at 30X - Head, clypeus READILY VISIBLE, hairs present but not so dense to hide surface - Difficult to separate from S. autumnalis (1)
S. brachycephalus vs. S. illinoensis vs. S. levis
S. brachycephalus - Thorax, propodeum, dorsal triangle striations, clearly DO NOT REACH THE RIM, leaving a shiny, pitless, unmarked area that extends like a triangle over the rim to the rear face where it comes to a point (1)
S. illinoensis - Thorax, propodeum, dorsal propodeal triangle striations, clearly go ALL THE WAY TO THE RIM of triangle, there may or may not be a carina along the rim, below the rim on the rear face of the propodeum is a clear unmarked, shiny triangle whose base is along the rim and the tip of which runs about half way down - Abdomen, T1 pitting at 30X, FINE but CLEARLY EVIDENT and about 1-2 pit diameters apart - In the other species, abdominal pits are very difficult to detect at 30X and visible only at certain angles (1)
S. levis - Thorax, propodeum, dorsal propodeal triangle striations, clearly go ALL THE WAY TO THE RIM of the triangle, there may or may not be a carina along the rim, below the rim on the rear face of the propodeum is a clear unmarked, shiny triangle whose base is along the rim and the tip of which runs about half way down - Propodeum, rear face, striations forming LARGE OPEN RETICULATIONS, these striations are of the same height as the striations on the propodeal triangle, but in the other species these striations are low and obscure (1)
S. clematidis vs. S. hydrangeae vs. S. prosphorus vs. S. ranunculi
S. clematidis - Head, 1st flagellar segment AS LONG or longer than pedicel - Frons, surface of face below antennae, LARGELY HIDDEN by bright white hair - Antennae, outer flagellar segments farthest from pedicel, STRONGLY FACETED - Abdomen, T2, with an UNPITTED RIM occupying ONE QUARTER or more of the longitudinal length of the segment - Very similar to S. prosphorus, but in direct comparison, the unpitted rim of T2 in S. clematidis is longer longitudinally than the other species (1)
S. hydrangeae - Head, 1st flagellar segment CLEARLY LONGER THAN pedicel - Frons, surface of face below antennae, LARGELY EXPOSED with scattered hairs present - Antennae, outer flagellar segments farthest from pedicel, NOT strongly faceted, facets restricted to edges of joints between segments (1)
S. prosphorus - Head, 1st flagellar segment AS LONG or longer than pedicel - Frons, surface of face below antennae, LARGELY HIDDEN by bright white hair - Antennae, outer flagellar segments farthest from pedicel, STRONGLY FACETED - Abdomen, T2, with an unpitted rim occupying one fifth or less of the longitudinal length of the segment - Very similar to S. clematidis, but can be distinguished by the T2 rim (1)
S. ranunculi - Head, 1st flagellar segment SHORTER than pedicel - Leg, mid-femur, CLEARLY MUCH WIDER than the rear femur, in the other species the femurs are about the same size (1)
S. cressonii vs. S. levis
S. cressonii -Difficult to separate from S. levis, identified males appear to be identical (1)
S. levis - Difficult to separate from S. cressonii, identified males appear to be identical (1)
S. dichrous vs. S. hydrangeae
S. dichrous - Abdomen, in comparison with S. hydrangeae, pit density slightly HIGHER and hair density slightly GREATER - Very difficult to tell apart from S. hydrangeae without a long series or without looking at the genitalia (1)
S. hydrangeae - Abdomen, in comparison with S. dichrous, pit density slightly LOWER and hair density EXTREMELY SPARSE - Very difficult to tell apart from S. dichrous without looking at a long series or at the genitalia (1)
S. galerus vs. S. smilacinae
S. galerus - Thorax, scutum, pitting, DENSE with spaces between pits, almost entirely, far less than 1 pit diameter (1)
S. smilacinae - Thorax, scutum, pitting, relatively SPARSE, with many spaces between pits far exceeding 1 pit diameter (1)
S. hydrangeae vs. S. minor
S. hydrangeae - Head, antennal facets, may or may not be PRESENT, if present, it distinguishes this species from S. minor - Pedicel, about HALF OR LESS of the length of F1 - Thorax, scutellum, surface texture, about as rough as that of the metanotum, so ROUGH and rugose that pits do not appear to be present (1)
S. minor - Head, antennal facets, always WITHOUT antennal facets - Pedicel, about THREE QUARTERS of the length of F1 - Thorax, scutellum, surface texture, clearly PITTED with a SMOOTH surface (1)
S. mandibularis vs. S. minor vs. S. pimpinellae
S. mandibularis - Head, 1st flagellar segment, HALF OR MORE the length of the second flagellar segment - Antennae, length of flagellar segment 7-9, about the SAME AS THE WIDTH - Thorax, propodeum, below the rim on the rear face, a clear UNMARKED, SHINY triangle whose base is along the rim and the tip of which runs about half way down - Difference between this species and S. pimpinellae is unclear (1)
S. minor - Head, 1st flagellar segment, HALF OR LESS the length of the second flagellar segment - Antennae, length of flagellar segment 7-9, about 1.5X the width - Thorax, propodeum, below the rim of the rear face, entirely reticulated with RAISED LINES, no unmarked triangle present (1)
S. pimpinellae - Head, 1st flagellar segment, about TWO-THIRDS the length of the second flagellar segment - Antennae, length of flagellar segment 7-9, about the SAME AS THE WIDTH - Thorax, propodeum, below the rim on the rear face, a clear UNMARKED, SHINY triangle whose base is along the rim and the tip of which runs about half way down - Difference between this species and S. mandibularis is unclear (1)
S.carolinus vs. S. smilacinae vs. S. solonis
S. carolinus - Head, clypeus, surface CLEARLY VISIBLE, hairs thin and scattered (1)
S. smilacinae - Head, clypeus, surface CLEARLY VISIBLE, hairs thin and scattered - Clypeus and face, while containing numerous hairs, has NO THICKER, bright white, minutely plumose HAIRS that show up on in the other species, particularly in the area to either side of the clypeus (1)
S. solonis - Head, clypeus, surface LARGELY DISGUISED by thick white hair - Thorax, propodeum, entire rear face of the propodeum strongly reticulated with RAISED LINES, the other species have a clear shiny, unmarked and unpitted triangle whose base runs along the rim of the dorsal triangle and runs down to the point about half way or a bit more on the rear face of the propodeum (1)
S.johnsonii vs. S. pimpinellae
S. johnsonii - Size 8-9mm - Head, flagellar segments 7-9, SLIGHTLY LONGER than broad - In direct comparison to S. pimpinellae, is a slightly larger, stouter, duller, hairier, more densely pitted bee with a slightly longer antennae - A frustrating pair, S. johnsonii and S. pimpinellae, as in direct comparison they are easy to separate, but definitive characters that are easy to portrait are difficult to come up with (1)
S. pimpinellae - Size 7-8mm - Head, flagellar segment 7-9, about AS LONG AS BROAD - In direct comparison with S. johnsonii, is a smaller, slimmer, shinier, less hairy and less distinctly pitted bee with slightly shorter antennae - A frustrating pair, S. johnsonii and S. pimpinellae, as in direct comparison they are easy to separate, but definitive characters that are easy to portrait are difficult to come up with (1)
Species currently listed as subspecies, but now thought to be species
1. RECOMMENDED - Include this species (41)
2. DROP this species from the list (40)
Species for which only the females are known
1. RECOMMENDED - Drop these species from the list (38)
2. DISPLAY these species (3)
Species thought to be synonyms of other species
1. RECOMMENDED - Drop these species from list (35)
2. DISPLAY these species (6)
Thorax, pronotum, lateral or humeral angle, shape
Greater than 90 deg (30)
90 degrees or less (10)
Thorax, pronotum, lateral or humeral ridge, shape
Ridge rounded over, not sharply defined (25)
Strongly angled, with a sharp clear edge (21)
Thorax, propodeum, triangle, percent distance from the base to the rim that raised reticulations or striations are present
100 (31)
50 - 95 (7)
Less than 50 (2)
Thorax, scutum, pits in the center
All pits touching one another (21)
Many pits touching one another (12)
Some pits touching one another (11)
No pits touching on another (9)
Total length in millimeters
6 (21)
7 (21)
8 (19)
9 (17)
5 (15)
10 (9)
4 (9)
11 (5)
3 (2)