|
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 is a small dark species closely related to plumosa and to
lupina. The females of metenua can be separated from those of
lupina by their longer ultimate flagellar segment and by the hairs
of the head being all or almost all black. The females are dis-
tinguished from those of plumosa by the darker vestiture, as de-
scribed below, and by the usually shiny galeae. The males of
metenua are readily distinguished from those of lupina by the form
of the flagellar segments, as described below, and by the shiny,
usually unshagreened galeae. The males of metenua are exceed-
ingly similar to those of plumosa. However, in metenua the galeae
are usually unshagreened and shiny and the clypeus is brighter in
color and more coarsely punctate than in plumosa.
Female. Measurements and ratios: N, 20; length, 9.0-11.5 mm.;
width, 3-4 mm.; wing length, M = 3.32 0.149 mm.; hooks in
hamulus, M = 11.95 0.114; flagellar segment 1/segment 2, M =
1.89 0.003.
Structure and color: Integumental color as in M. lupina with the
following exceptions: eyes grayish green to bluish green; wing
membranes slightly infumate, veins dark brown to black; tibial
spurs rufescent to yellowish brown.
Sculpturing and structure as in lupina with the following differ-
ences: clypeal punctures round, separated mostly by less than
half a puncture width, surface moderately shiny, somewhat dulled
by transverse shagreening, especially posteriorly; supraclypeal area
with the surface shiny, unshagreened or sparsely so; vertex with
lateral flattened areas at apices of compound eyes shiny, punctures
separated mostly by one or more puncture widths; apical flagellar
segment distinctly longer than broad, rounded distally, eyes often
slightly more than three times as long as broad; maxillary palpal
segments in ratio of about 2.3:2.3:2.0:1.0, occasionally with a
minute fifth segment; galeae with surface usually shiny and unsha-
greened or with extremely delicate, reticular shagreening. Meso-
scutum with posteromedian area often impunctate, surface not
usually dulled by shagreening anteriorly or laterally; scutellum
with surface not shagreened; metanotum usually shiny medially;
mesepisternum with punctures separated mostly by half a puncture
width or less, surface shiny, delicately or not shagreened. Meta-
somal tergum | with basal half punctate, medially separated mostly
by more than one puncture width and many by two or more punc-
ture widths; tergum 2 with basal depressed area with round
punctures separated by one to two puncture widths, with interband
zone punctures small, separated mostly by two puncture widths
or more in lateral raised areas, apical area essentially impunctate
or with few shallow punctures near pale pubescent band; tergum 3
similar but punctures of basal and interband zones more crowded;
pygidial plate narrowly V-shaped with rounded apex.
Hair: Vestiture variable; darkest individuals with hairs all black
except scopal hairs pale yellow to whitish on tibia and pale yellow
to brown on basitarsus, and outer surface of fore and middle tibiae
white apically. The palest specimens are as follows: head hairs
all black; thoracic hairs black to dark brown except mesoscutum
pale ochraceous on anterior third and at extreme sides, scutellum
fringed with pale, metanotum and propodeum above with pale, and
mesepisternum with upper third of lateral surface with ochraceous
hairs; metasomal tergum 1 with a few pale hairs mixed with the
dark in basal half; tergum 2 with narrow lateral oblique fasciae of
cinereous pubescence, fasciae separated by at least length of one
fascia; tergum 3 with distal pale band of cinereous pubescence not
reaching apex of tergum; tergum 4 with apical band of pale pubes-
cence separated from apex in 5 and 6 with hairs all dark; scopal
hairs pale yellow to white except brown near basitibial plate ancapically and laterally on basitarsus; fore and middle tibiae often
white on outer surface near apex. In individuals between these two
extremes pale hairs appear in the following order: first, in the
pale fasciae of tergum 3 and on dorsal surface of propodeum and
metanotum; second, laterally on tergum 4 and fringing scutellum
and anteriorly on mesoscutum; third, on tergum 2, on mesepisterna and on base of tergum 1.
Male. Measurements and ratios: N, 20; length, 8-11 mm.; width,
2.5-3.5 mm.; wing length, M = 3.01 0.182 mm.; hooks in hamu-
lus, M= 11.15 0.150; flagellar segment 2/segment 1, M = 4.39
0.087.
Distribution. California north to Washington, east to Idaho and
northwestern Wyoming, and south to northern Utah (Fig.5). This
species has been collected from June 8 until September 15, but
mostly during July and August. In addition to the type material, 87
females and 86 males (of which 75 females and 76 males are from
Oregon) have been examined from the localities listed below.
Flower records. Cosmos sp., Erigonum sp., Melilotus alba. Only
one of the females examined had collection data regarding the
flowers it was visiting. This female was visiting Melilotus alba.
Therefore, no statement regarding flower habits can be made at this
time.
|
