Extracted from: Sheffield C. S., et al (2011). Leaf cutter and Mason Bees of the Genus Megachile Latreille (Hymenoptera; Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification No. 18|
Megachile (Megachiloides) sublaurita Mitchell, 1927 New Combination
Megachile laurita sublaurita Mitchell, 1927. Psyche 34: 117 (♀).
Megachile (Megachiloides) subanograe Mitchell, 1934. Trans. Amer. Entomol. Soc. 59: 344 (♀). New synonymy.
Diagnosis. The female of M. sublaurita can be recognized by the combination of 3-dentate mandibles, smaller body size (9-10 mm), and more closely punctate T5 and T6. They are most similar to M. anograe and M. umatillensis. The female of M. anograe is generally larger (12-13 mm), with T5 and T6 shiny and sparsely punctate (with shiny interspaces of 3-4 pd). The female of M. umatillensis has a 4-dentate mandible. The male of M. sublaurita is recognized by the combination of a conspicuously pale coloured and greatly modified front leg, rounded postmedian tranverse carina on T6, T5 with a white, apical fascia, mandible with basal process pointed apically, hind tarsomeres subtriangular (i.e., broader apically) and pubescent, mesepisternum without protuberance, pubescence of legs largely pale, apical flagellomere broadly flattened. They are most similar to M. casadae, M. anograe and M. umatillensis; less so to M. fortis, M. wheeleri, M. manifesta, and M. subnigra. The male of M. casadae has the clypeal surface shiny and sparsely punctate. The male of M. anograe has T5 without a white, apical fascia. The male of M. umatillensis has the apical flagellomere unmodified. The male of M. fortis is very large, and has the mandible with basal process broadly truncate. The male of M. wheeleri has the hind tarsomeres quadrate, smooth and shiny, and the mesepisternum with a prominent, flattened, triangular carina-like protuberance just behind the front coxa. The male of M. manifesta has the mesepisternum with a smoothly rounded carina just behind the front coxa. The male of M. subnigra has the pubescence of the legs primarily black.
Female: Length 9-10 mm.
Head. 1) compound eyes subparallel; lateral ocelli subequally distant from eyes and edge of vertex, 2) clypeal margin nearly straight, thickened and impunctate medially, slightly outcurved, 3) mandible 3-dentate, the two apical teeth approximate, with a long cutting edge between 2nd and inner teeth (Plate 1, Figure M22), 4) gena subequal to compound eye in width, 5) punctures fine and close on vertex medially, and most of face below ocelli, and on clypeus basally, becoming more coarse apically, more coarse and sparse on gena below, on vertex laterally and between compound eyes and ocelli, interspaces ≤ 1 pd, 6) pubescence entirely white on head, sparse on most surfaces, hardly concealing surface beneath except around base of antennae, 7) F1 longer than broad (2:1.5), subequal in length to pedicel, distinctly longer than F2, which is slightly broader than long, remaining flagellomeres subquadrate, apical flagellomere more elongate (3.5:2).
Mesosoma. 1) pubescence sparse and entirely white, more elongate laterally and posteriorly, copious around pronotal lobe and wing base, 2) punctures relatively coarse and close on mesoscutum and scutellum, with shiny interspaces ≤ 1 pd present medially on mesoscutum, scutellum with a distinct impunctate area medially, punctures relatively coarse, deep and sparse on pleura, propodeum shiny with punctures fine and sparse, triangle shiny and impunctate, 3) mid and hind basitarsi distinctly shorter and narrower than their tibiae, hind spurs brown, the front and middle ones yellowish, 4) tegula yellowish-red, finely punctate, becoming more sparse in posterior half, 5) wings hyaline, very slightly clouded apically, the veins reddish-brown.
Metasoma. 1) T2-T5 very slightly depressed basally, without a distinct carinate rim, depressed somewhat apically; T6 triangular in dorsal aspect, narrowly subtruncate apically with the sides straight, straight in profile with abundant erect hair visible; all of the terga shining; punctures minute and close on T1 and T2, becoming increasingly sparse but also fine to T5, somewhat less sparse on T6; pubescence entirely white on T1-T4, T5 and T6 with sparing black pubescence laterally, T1-T5 with white apical fasciae, dense on the more apical terga, narrower medially on the more basal ones, 2) scopa white, entirely black on S5 and S6;punctures fine and close on basal sterna, becoming coarse and more spaced apically, with shiny interspaces.
Male: Length 10-11 mm.
Head. 1) compound eyes subparallel; lateral ocelli subequally distant from eyes and edge of vertex, 2) clypeal margin produced medially, projection shiny and impunctate, 3) mandible 3-dentate, the 2nd tooth much closer to the apical tooth than the inner one, lower process acute, subbasal in position, 4) gena equal to compound eye in width, 5) punctures fine, shallow, but rather close on gena, becoming deeper and more distinctly separated on vertex and between lateral ocelli and eyes, fine and close on face below median ocellus, clypeus shiny, punctures fine and well separated (>1 pd), 6) pubescence almost entirely white on head, dense and elongate on face below median ocellus, on clypeus and supraclypeal area, gena below, and medially on vertex, vertex laterally and along upper margin of eye with sparse, short, and erect black pubescence, 7) F1 about as long as broad, subequal in length to pedicel and F2, which is quadrate, the remaining flagellomeres slightly longer than broad (4:3), apical flagellomere flattened and broadly dilated.
Mesosoma. 1) pubescence entirely pale on dorsal surface and propodeum, with dense white tufts at edges of pronotal lobe and behind wing base, pale on legs, the front tarsal fringe pale and long, with dark tipped hairs on the underside, mid tarsal fringe pale, long and conspicuous, 2) punctures fine and distinctly separated near centre of mesoscutum, more so on scutellum medially, becoming more crowded on pleura, propodeum with fine well spaced punctures, triangle smooth and impunctate, 3) front coxal spine narrow and elongate, broader at base, with a patch of reddish bristles on outer half of base, sparse elongate pubescence on undersurface, coxal surface otherwise bare; front femur dark on outer surface, otherwise yellowish with lower margin rounded and carinate, front tibia dark on outer face except for the yellowish apex, front tarsus yellowish and slightly dilated, front basitarsus distinctly narrower than its tibia, the anterior margin excavated, tarsomeres 2 and 3 with a dark spot ventrally, mid and hind tarsi dark red, hind basitarsus very short and narrow, less than half as long as its tibia, 4) tegula dark red, shiny, finely and sparsely punctate, 5) wings subhyaline, the veins dark brown.
Metasoma. 1) terga slightly depressed basally, but without carina, more deeply depressed apically; carina of T6 entire, slightly irregularly crenulate, produced medially into a triangular point that points downward, the apical margin with pronounced carinate median teeth, the lateral teeth inconspicuous; T7 conspicuous, produced medially into an acute spine; punctures minute, shallow and close on metasoma basally, but becoming quite sparse on the shining, more apical terga, T6 more finely and closely punctate; pubescence sparse and entirely pale on discs of T2-T5, copious on T1, T5 with pale tomentum basally, complete white apical fasciae on T1-T5, 2) S1-S4 visible, apical margins depressed and hyaline, discs shiny and sparsely punctate, apical fringe of long white hairs on S1-S3, absent medially on S4.
Genitalia. Plate 2.
Discussion. This species has been collected only rarely in Canada, although it is much more common in the United States. The male is described here for the first time. Like M. anograe and M. subnigra, this species has pale and melanistic forms which show no differentiation in CO1 sequences. The pale form (i.e., M. subanograe) is much more common and widespread in North America, and is the only form occurring in Canada. This species nests in the ground.
Distribution. Southern AB, east of the Rocky Mountains.