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Extracted from: LaBerge, W. E., 1961. A Revision of the Bees of the Genus Melissodes in North and Central America. Part III (Hymenoptera, Apidae). The University of Kansas Science Bulletin, Vol. 43. 1-107.
This species is closely allied to M. composita Tucker. The fe-
males are distinguished from those of composita primarily by the
less coarse punctation of the mesoscutum and first metasomal
tergum. The males of lustra can be distinguished from those of
composita by the less coarse sculpturing of the mesoscutum and by
the shape of the median and lateral plates of sternum 7 as described
below.
Female. Measurements and ratios: N, 20; length, 9-12 mm.;
width, 3.0-4.5 mm.; wing length, M = 3.56 0.168 mm.; hooks in
hamulu, M = 12.70 0.147; flagellar segment 1/segment 2, M =
2.05 0.027.
Male. Measurements and ratios: N, 20; length, 9-12 mm.; width,
2.5-3.5 mm.; wing length, M = 3.31 0.153 mm.; hooks in hamu
lus, M = 11.95 0.185; flagellar segment 2/segment 1, M = 3.45
0.067.
Structure and color: Integumental color as in lupina except eyes
yellowish green to green. Sculpturing and structure as in composita
with the following differences: supraclypeal area often dulled by
reticular shagreening; maxillary palpal segments in ratio of about
2:2:2:1; mesoscutum with punctures mesad of parapsidal lines
small to minute, separated mostly by more than one puncture width
(often by three or four puncture widths ), punctures laterad of parap-
sidal line small, separated by one-half to one puncture width,
posteromedian impunctate area large; scutellar punctures irregular
in size, medially separated by one-half to two puncture widths;
mesepisterna with punctures shallow, as large or larger than meso-
scutal punctures mesad of parapsidal lines, surface dulled by fine
shagreening; metasomal tergum 1 with basal sixth with crowded
punctures, from basal sixth to about three-fifths of median length
with scattered punctures separated by two to four puncture widths,
apical area impunctate; tergum 2 with basal zone punctures minute,
separated mostly by one puncture width and surface shiny, inter-
band zone with scattered, irregular-sized punctures, apical area im-
punctate, surface moderately shiny, reticulotransversely shagreened;
tergum 3 similar to tergum 2 but interband zone punctures sparser
than in composita, medially separated mostly by two or more punc-
ture widths; pygidial plate narrow, U-shaped with sides subparallel
in apical third (somewhat V-shaped when worn near tip ).
Hair: Hair color as in composita with the following additions:
head often with dark brown mixed with pale on face along inner
margins of compound eyes (as in holotype ) to occasional specimens
in which head all dark brown except golden on labrum; thorax often
with a few long brown hairs mixed with the pale on pronotum (as in
holotype ) and especially on posterior pronotal lobes to occasional
specimens in which lateral surfaces of thorax and pronotum with all
hairs dark brown to black and dark mixed with the pale on anterior
and lateral parts of mesoscutum; metasomal terga 5 and 6 occasion-
ally with median hairs dark brown ( golden in holotype and in most
specimens, even on some in which the head and thorax are mostly
dark); legs with hairs as in composita (and in holotype of lustra)
but darkest specimens with coxae, trochanters, femora and fore
tibiae pale brown and inner surfaces of hind basitarsi red.
Distribution. M. lustra occurs from Baja California in the south-
west, north to Oregon and east to Utah and Idaho (Fig. 7). It
has been collected between the dates of August 7 and November 19
(one label bears the month of July and the specimen was pre-
sumably taken near the end of that month).
Flower Records. Aster sp., Baccharis pilularis, Biglovia sp..,
Chrysothamnus sp., C. nauseosus, C. nauseosus consimilis, C. nau-
seosus speciosus, C. v. viscidiflorus, C. viridulus, Croton californi-
cus, Ericameria palmeri, Eriogonum latifolium, Grindelia sp., G.
camporum, Gutierrezia californica, G. sarothrae, Haplopappus
bloomeri angustatus, Helianthus sp., Heterotheca grandiflora, Iso-
coma sp., I. vernonioides, Melilotus alba, Senecio douglasii.
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