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Megachile umatillensis (Mitchell, 1927)
Megachiloides umatillensis Mitchell, 1927

Life   Insecta   Hymenoptera   Apoidea   Megachilidae   Megachile
Subgenus: Megachiloides

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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) umatillensis (Mitchell, 1927)

Megachiloides umatillensis Mitchell, 1927. Psyche 34: 118 (♂, ♀)

Diagnosis. This is a distinct species. The female of M. umatillensis can be recognized by the extremely long tongue, and also by the combination of 4-dentate mandibles (the third tooth a small angle interrupting the long cutting edge between 2nd and inner teeth), and the large body size (13-15 mm). They are most similar to M. anograe. The female of M. anograe is generally smaller (12-13 mm), has a shorter tongue which is typical in length to most Megachile in Canada, and has a distinctly 3-dentate mandible. The male of M. umatillensis also has a long tongue and larger body size (13 mm), and is further recognized by the combination of an unmodified apical flagellomere, 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. They are most similar to M. casadae and M. anograe; less so to M. fortis, M. wheeleri, M. manifesta, M. sublaurita and M. subnigra, all of with have a shorter tongue and the apical flagellomere which is flattened and dialated to some degree.

Female: Length 13-15 mm.

Head. 1) compound eyes subparallel; lateral ocelli subequally distant from eyes and edge of vertex, 2) clypeal margin nearly straight, slightly thickened and narrowly impunctate medially, 3) mandible 4-dentate, the two apical teeth approximate, the 3rd tooth a small angle interrupting the long cutting edge between 2nd and inner teeth (Plate 1, Figure M24), 4) gena slightly wider than compound eye (6:5), 5) punctures fine and close on vertex and most of face below ocelli, on clypeus basally, becoming more coarse and slightly more sparse apically, and on lower half of gena, 6) pubescence white on most of head, with short, erect black hairs across vertex, pubescence sparse on most surfaces including clypeus, hardly concealing surface beneath, becoming longer and dense on face below median ocellus, 7) F1 longer than broad (3:2), subequal in length to pedicel, distinctly longer than F2, which is slightly broader than long, remaining flagellomeres subquadrate to slightly longer than broad, apical flagellomere more elongate, about twice as long as broad.

Mesosoma. 1) pubescence sparse and entirely pale, more elongate laterally and posteriorly, copious around pronotal lobe and wing base, 2) punctures relatively coarse and close on mesoscutum and scutellum, with dull interspaces ≤ 0.5 pd, slightly more separated (≤ 1 pd) medially on mesoscutum, punctures relatively coarse, and close on pleura, propodeum dull with punctures fine and shallow, triangle dull 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 reddish, finely punctate throughout, densely pale pubescent on apical half, 5) wings hyaline, very slightly clouded apically, the veins reddish-brown.

Metasoma. 1) T2-T5 very slightly depressed basally, with a distinct carinate rim, depressed somewhat apically; T6 triangular in dorsal aspect, subtruncate apically, straight to very slightly concave in profile with abundant erect hair visible; terga somewhat shining; punctures minute, close (<0.5 pd) and rather shallow on T1-T3, becoming increasingly deeper, coarser and more sparse (≤ 1 pd) to T5, somewhat less sparse on T6; pubescence entirely pale on T1 and T2, T3 with some dark pubescence medially, pale basally, T4-T6 mostly black pubescent, with a few scattered plae hairs laterally, T1-T5 with entire white apical fasciae, 2) scopa white, entirely black on S6; punctures fine and close on basal sterna, becoming coarse and more spaced apically, with shiny interspaces.

Male: Length 13-14 mm.

Head. 1) compound eyes subparallel; lateral ocelli closer to eyes than to edge of vertex (4:5), 2) clypeal margin straight, 3) mandible 3-dentate, the 2nd tooth median in position, lower process acute, subbasal in position, 4) gena subequal to slightly broader (5:6) than compound eye, 5) punctures fine, shallow, but rather close on gena, becoming deeper on vertex and between lateral ocelli and eyes, fine and close on face below median ocellus, 6) pubescence almost entirely white on head, dense and elongate on face below median ocellus, on clypeus and supraclypeal area, and medially on vertex, vertex laterally and along upper margin of eye with sparse, short, and erect dark brownish-black pubescence, gena with pubescence shorter and more sparse, depression on lower area adjacent to mandible with a tuft of short, dense, yellowish-brown hair, 7) F1 slightly longer than broad, and slightly longer than pedicel which is about as long as broad, and shorter than the remaining flagellomeres, which are slightly longer than broad (3:2), apical flagellomere unmodified, much longer than broad (5:2).

Mesosoma. 1) pubescence long and 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 thickened dark hairs on the underside, mid tarsal fringe pale, long and conspicuous, 2) punctures fine and close dorsally on mesoscutum and scutellum, distinctly separated (≤ 1 pd) on centre of mesoscutum, becoming more crowded on pleura, propodeum with fine well spaced punctures, triangle smooth, dull and impunctate, 3) front coxal spine narrow and elongate, with a patch of reddish bristles at base, sparse elongate pubescence on undersurface, with a dense tuft of pale hair at tip of spine, coxal surface otherwise largely bare; front femur dark with lower margin rounded, front tibia dark except for the yellowish apex, front tarsus yellowish-brown and dilated, front basitarsus distinctly narrower than its tibia, the anterior margin excavated, tarsomeres with dark areas ventrally, mid and hind tarsi dark, hind basitarsus very short and narrow, less than half as long as its tibia, 4) tegula dark red, shiny, finely and sparsely punctate throughout, apical half with white pubescence, 5) wings subhyaline, the veins reddish-brown.

Metasoma. 1) terga deeply depressed basally, with a distinct carina, apical margin deeply depressed; 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 subtrianglual, small, but conspicuous; T7 conspicuous, produced medially into an acute triangle; punctures minute, shallow and close on T1 and T2, more sparse (1 pd) on T3, becoming larger and elongate on T4 and T5, especially on apical 1/3, T6 more closely punctate, punctures becoming subrugose apically; 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, S3 and S4 with surface apical to depression rugose, apical edges narrowly hyaline, widely so on S4, discs rather dull and sparsely punctate, punctures of S4 fine, shallow, and sparse, apical fringe of long white hairs on S1-S3, narrowed medially on S3, absent medially on S4.

Genitalia. Plate 2, Figure G24.

Discussion. This is the first record of this species in Canada, the single male specimen collected in southern British Columbia on June 23, 2010 (Haynes Lease Ecological Reserve; S. Elwell, collector), though the type locality is in adjacent Washington state (Camp Umatilla). Megachile umatillensis was one of three species (with M. oenotherae Mitchell and M. amica Cresson) originally placed in the subgenus Megachiloides (Mitchell 1936); Mitchell (1924) originally considered Megachiloides a genus with M. oenotherae the only species. He later (Mitchell 1934) added M. amica, M. umatillensis, but also M. laurita (=M. anograe), M. anograe, and three undescribed species; these were later added to Derotropis (Mitchell 1936). All three Megachiloides sensu stricto possess a long tongue in both sexes, and all are considered oligoleges of the plant genus Oenothera (Mitchell 1924, 1936; Bohart and Youssef 1972). This species nests in the ground.

Distribution. Southern BC.

Scientific source:

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FamilyScientific name @ source (records)
Onagraceae  Oenothera sp @ BBSL (6)

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Updated: 2019-10-20 03:03:34 gmt
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