Key to Laphria Meigen s. str. from Eastern North America

by S. W. Bullington


Couplet 1

    Ground color of femora orange; medium sized to large (16-25 mm long)
    wasp-like fly restricted to Coastal Plain . . . . .
saffrana Fabricius
    Ground color of femora dark reddish brown to blue black; bumble-bee
    like flies of variable size and geographic distribution . . . . .

Couplet 2

    Hair in front of wings, halteres, and on scutellum all yellow;
    upper portion of mystax black or mostly so (a few yellow hairs
    may be present centrally) . . . . .
Go to Couplet 3
    Hair in front of wings and/or in front of halteres and/or on
    scutellum black; upper portion of mystax variable . . . . .

Couplet 3

    Posterior surface of fore-tibiae, and anterior, dorsal, and
    posterior surfaces of mid-tibiae covered with extremely conspicuous
    long, bright yellow hairs; mesal third of posterior surfaces of
    hind tibiae each with a patch of sparse yellow hair, which is most
    distinct when viewed from above level of fly (i.e. looking "down"
    the tibiae from its base); first abdominal tergite covered with
    yellow hairs, except along extreme lateral margins, where some hairs
    are black; tergites 2-3 haired similarly; remaining tergites black
    haired; this fly is very similar to some individuals of the extremely
    variable L. thoracica, but can be readily recognized by its smaller
    size (15-20 mm long), more slender build, and invariable abdominal
    coloring; found from Wisconsin to Quebec and south to Connecticut
    . . . . .
sacrator Walker
    Fore- and mid-tibiae with some yellow hair, but this hair is never
    conspicuous; mesal third of posterior surfaces of hind tibiae
    entirely black haired; first abdominal tergite entirely black
    haired; hairing of tergites 2-3 extremely variable, from nearly
    all yellow to entirely black; abdomen often entirely black; this
    fly is in general larger (15-25 mm) and more stockily built than
    the similar L. sacrator, and is probabily the most convincing
    bumble-bee mimic in the entire genus; found throughout most of the
    eastern United States . . . . . .

Couplet 4 (2)

    Abdominal tergite 1 with yellow hairs laterally, black hairs
    medially; tergites 2-7 entirely black haired; scutellar hairs
    long and abundant on both disk and margin, bright yellow; small
    to medium-sized (11-20 mm) fly found throughout most of eastern
    United States . . . . .
flavicollis Say
    Abdominal tergite 1 either lacking yellow hairs laterally, and/or
    tergites 2-7 with yellow hairs present; scutellar hairs variable;
    body size and geographic distribution variable . . . . .

Couplet 5

    Abdominal tergites covered with layer of black hair; yellow hairs
    lacking; scutellar hairs black . . . . .
Go to Couplet 6
    Abdominal tergites with prominent areas of hairless cuticle and/or
    with yellow hairs present; scutellar hairs variable . . . . .

Couplet 6

    Mesonotum with pile appearing olive yellow from a distance; hind
    femora each with a thick flange of bright yellow hairs stretching
    dorsally from near base to about three-fourths way to apex; tufts
    of hair in front of halteres entirely black; medium-sized (15-24 mm)
    fly found along Atlantic seaboard from Cape Cod to Florida . . . . .
affinis Macquart
    Mesonotum with pile appearing bright yellow from a distance; hind
    femora entirely black haired; tufts of hair in front of halteres
    mostly yellow; slightly smaller (13-20 mm) fly found throughout
    most of the southeastern United States . . . . .

Couplet 7 (5)

    Mystax entirely black, except possibly for a few adventitous
    yellow hairs dorsally in male; hairs in front of wings, in front
    of halteres, and on scutellum all black; medium-sized to large flies
    (19-27 mm) found in Texas. . . . .
Go to Couplet 8
    Mystax yellow on upper portion of facial gibbosity, black on sides
    of oral cavity or lower portion: hair in front of wings, in front
    of halteres, and on scutellum variable; size and geographic
    distribution variable . . . . .

Couplet 8

    Male with about apical posterior third of each fore-tibia, and
    entire length of dorsal half of each mid-tibia, with extremely
    conspicuous yellow hairs; female similar, except that fore-tibiae
    are entirely black-haired; abdominal tergite 1 with substantial
    amount of yellow hair in both sexes; large (22-27 mm long) fly
    . . . . .
macquarti (Banks)
    Male with fore-tibiae, mid-tibiae, and abdominal tergite 1 entirely
    black haired; female unknown, but likely to be similar; slightly
    smaller (19 mm long) fly . . . . .

Couplet 9 (7)

    Thoracic mesonotum with a band of red hair across posterior
    margin; scutellum with red hair; small (13-18 mm long) fly found
    from Michigan, across Ontario and Quebec to Labrador . . . . .
insignis (Banks)
    Thoracic mesonotum and scutellum variable, but lacking red
    hair; size and geographic distribution variable . . . . .

Couplet 10

    Hairs on margin of scutellum entirely yellow, always long and
    conspicuous . . . . .
Go to Couplet 11
    Hairs on margin of scutellum all or mostly black, and sometimes
    short and inconspicuous . . . . .

Couplet 11

    Back of head with at least some black hairs fringing outside upper
    margin of eye; these hairs may be very inconspicuous; hind tibiae
    with only black hairs dorsally . . . . .
Go to Couplet 12
    Yellow hairs fringing eyes around entire outside margins; hind
    tibiae with many golden-yellow hairs dorsally; medium-sized
    (15-18 mm), stocky fly found from Michigan to Ontario . . . . .

Couplet 12

    Many black hairs on back of head and fronting upper third of margin
    of eye; hairs on disk of scutellum conspicuous and yellow; abdominal
    tergite 3 entirely with black hair; small to medium-sized (11-18 mm
    long) fly found in northeastern United States . . . . .
divisor (Banks)
    Back of head with just a few black hairs fronting upper fourth of
    margin of eye; hairs on disk of scutellum inconspicuous and black;
    abdominal tergite 3 with patches of yellow hairs to each side along
    posterior margin; small (10-15 mm long) fly found in Michigan . . . . .

Couplet 13 (10)

    Visible dorsum of all abdominal tergites except 5 entirely bare,
    showing a ground color of polished black; some hairs present along
    extreme lateral margins of all tergites; in the male all of these
    lateral hairs are black; in the female some of the hairs on tergites
    1-2 are yellow; in both sexes dorsum of tergite 5 similar to that
    of the other segments, except that the lateral hairs extend slightly
    further medially, and in the female form conspicuous yellow patches;
    very large to huge (28-35 mm long) fly from Florida . . . . .
apila (Bromley)
    Dorsum of at least some abdominal tergites with abundant hairs
    medially; size and geographic distribution variable . . . .

Couplet 14

    Tufts of hair in front of wings entirely pale . . . . .
Go to Couplet 15
    Tufts of hair in front of wings mostly or entirely black . . . . .

Couplet 15

    Hind femora each with a thick flange of pale hairs stretching
    dorsally from near base to about three-quarters way to apex; apex
    or "knee" with conspicuous tuft of pale hairs; all pale hairs on fly
    very light yellow, almost dirty white; small (10-16 mm long),
    lightly built fly found in northeastern United States. . . . .
cinerea (Back)
    Hind femora black haired, except possibly for a few inconspicuous
    pale hairs on apex or "knee;" all pale hairs on fly bright yellow;
    larger (19-24 mm long), stockier flies; geographic distribution
    variable . . . . .

Couplet 16

    Abdominal tergite 6 covered with red hair; described from single
    large (26 mm long) female taken at Yonah Mountain, Georgia . . . . .
fattigi (Bromley)
    Abdominal tergite 6 black-haired; slightly smaller (19-24 mm long)
    fly; geographic distribution variable . . . . .

Couplet 17

    Abdominal tergite 5 with black hair medially and posteriorly:
    apices or "knees" of hind femora entirely black haired; stocky,
    medium-sized to large (19-24 mm long) fly found in northeastern
    United States . . . . .
champlainii (Walton)
    Abdominal tergite 5 entirely covered with yellow hair; apices
    or "knees" of hind femora with a few, scattered very inconspicuous
    yellow hairs, which cannot be seen without using a dissecting
    microscope at over 40X ; stocky, medium-sized (20 mm long) fly
    found in eastern portions of Kansas and Nebraska . . . . .

Couplet 18 (14)

    Abdominal tergite 1 entirely black haired . . . . .
Go to Couplet 19
    Abdominal tergite 1 with substantial amount of yellow hair . . . . .

Couplet 19

    Abdominal tergite 3 with black hairs medially; yellow hairs
    restricted to dorsolateral patches along posterior margin; male
    with posterior margin of basistylus smoothly curved; small to
    medium sized (12-18 mm long) fly; found in northeastern United
    States . . . . .
posticata posticata Say
    Abdominal tergite 3 with yellow hairs medially; these hairs may
    be partially rubbed off in some older males; male with posterior
    margin of basistylus irregular or "notched;" large to huge
    (23-39 mm long) fly; geographic distribution variable . . . . .

Couplet 20

    Light hairs bright to dull yellow ; tufts of hair in front of
    halteres entirely dull yellow; large to huge (23-35 mm long)
    fly found from New England to South Carolina, with stragglers
    into Florida . . . . .
grossa (Fabricius)
    Light hairs very dirty yellow to brownish yellow; tufts of hair
    in front of halteres with some black; very large to huge
    (27-39 mm long) fly apparently restricted to the western portion of
    the lower Mississippi Valley, from easten Texas and southeastern
    Kansas, east to Missouri . . . . .

Couplet 21 (18)

    Hind femora each with a dorsal flange of long yellow hairs, reaching
    from near base to about three-fourths way to apex; apices or "knees"
    entirely black haired; abdominal tergite 4 with yellow hairs
    restricted to thin band along anterior margin; a moderately large
    (22-27 mm long) fly restricted to Florida . . . . .
floridensis (Bromley)
    Hind femora with black hairs dorsally; apices or "knees" with
    a few, scattered very inconspicuous yellow hairs, which cannot
    be seen without using a dissecting microscope at over 40X;
    abdominal tergite 4 covered with yellow hair, except for a few
    black hairs and bristles at the extreme lateral margins; a
    medium-sized (15-20 mm long) fly found from the Lake states to
    Vermont and North into southern Canada . . . . .

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