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Megachile texensis Mitchell, 1956
Chalicodoma (Chelostomoides) texensis (Mitchell, 1956)

Life   Insecta   Hymenoptera   Apoidea   Megachilidae   Megachile
Subgenus: Chelostomoides

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Extracted from: Snelling R.R., (1990). A Review of the Native North American Bees of the Genus Chalicodoma (Hymenoptera: Megachilidae). Contributions in Science, Number 421, pp. 1-39.

This species was described from a single female collected at Southmost, Cameron Co., Texas; the type is in the USNM, and I have examined it. Al-though C. texensis barely enters the United States, it is widely distributed in Mexico and extends south to Costa Rica.

The male has not been previously described and both sexes are redescribed to provide a comparative basis for the very similar C. axyx, described above. Costa Rican females differ from those of Mexico (and the type) in having larger and stouter submedian clypeal tubercles and the process of the disc blunter (Fig. 54). Males from the two areas are more similar, but those from Costa Rica are, on the average, more densely punctate on the frons and vertex.

FEMALE. Measurements (mm): HW 2.92-3.28; HL 2.31-2.62; WL 6.0-6.5; TL 9.0-10.5.

Head (Fig. 54) about 1.3 times as broad as long; inner eye margins weakly divergent below, upper interorbital distance about 0.8 times lower inter-orbital distance; in frontal view, vertex strongly elevated above eyes and ocelli. Mandible slender, with three distinct apical teeth and an obscure denticle in second interspace; submedian angulation of upper margin weak, margin between it and third tooth shallowly concave and about as long as apical width of mandible (Fig. 22). Sides of labrum mostly subparallel, narrowed preapically; apical margin transverse; with median preapical seta-pit with cluster of long, reddish setae and small pit on either side with a single long seta arising from each. Clypeal margin broadly concave, with a pair of prominent submedian denticles; disc elevated along midline, with large conoid projection above and between submedian denticles of margin (Fig. 57); disc shiny between subcontiguous to contiguous coarse punctures, impunctate in middle. Supraclypeal area slightly elevated toward base of clypeus, punctation similar to that of clypeus. Punctation of frons, vertex, preocciput, and gena as in male but interspaces shiny. Pedicel about 1.5 times longer than either first or second flagellar segments. Interocellar distance greater than ocellocular distance; ocellocular distance equal to, or a little greater than, ocelloc-cipital distance.

Mesoscutum and scutellum as in male but interspaces shiny; mesepisternum shiny between sub-contiguous to dense, moderate punctures; metepi-sternum and side of propodeum moderately shiny between moderate, subcontiguous punctures; remainder of propodeum as in male.

Disc of first two terga moderately shiny between fine, subcontiguous to dense punctures; third and fourth terga similar but punctures less distinct, more separated; punctures of fifth tergum a little coarser, dense; sixth tergum finely, subcontiguously punctate, without preapical groove.

Pubescence about as in other Chelostomoides.

Clypeal hairs sparse, a few at sides somewhat brownish; supraclypeal area with a few brownish hairs interspersed among usual white hairs; hairs brownish on vertex and occiput and with some scattered brownish hairs on mesoscutum and scu-tellum; pronotal collar and mesoscutum without definite patches of flocculent hairs; first five terga with apical fringes of short, flocculent, appressed, white hairs; second and third terga with pubescent fasciae in basal gradular depression; discs of second to fifth terga with blackish pubescence only; sixth tergum wholly dark pubescent; scopa slightly yellowish, except blackish on apical segment.

MALE. Measurements (mm): HW 2.76-3.29; HL 2.14-2.52; WL 5.8-6.4; TL 8.0-10.5.

Head about 1.3 times as broad as long; inner eye margins weakly convergent below, upper interor-bital distance about 1.1 times lower interorbital distance; in frontal view preoccipital margin ar-cuately produced above ocelli by less than transverse diameter of anterior ocellus. Mandible without ventral process; apex tridentate, inner tooth on same plane as first and second teeth. Lateral margins of labrum slightly convergent apicad, apex truncate, disc shiny, nearly impunctate on basal one-half or less, integument slightly roughened between fine, dense punctures on distal one-half or more. Clypeus weakly convex, apical margin weakly produced in middle and shallowly emarginate, shorter than length of lateral margin between process and angle at eye margin; punctures of disc contiguous, fine to moderate over most of disc, becoming fine to minute toward apical margin; median impunctate line present but often weak, interspaces smooth and shiny. Supraclypeal area and frons slightly shiny, variably finely rugosopunctate to contiguously punctate; vertex and preocciput slightly shiny be-tween fine contiguous to subcontiguous punctures. Gena about half as wide as eye in profile, shiny between fine contiguous to subcontiguous punctures. Pedicel about as long as first flagellar segment; first flagellar segment distinctly broader than long and about one-half as long as second flagellar segment. Interocellar and ocellocular distances sub-equal and longer than ocelloccipital distance.

Mesoscutum and scutellum moderately shiny and weakly tessellate between subcontiguous fine to moderate punctures; metanotum less shiny, punctures fine and close to dense; mesepisternal punc-tation similar to mesoscutum but interspaces a little less shiny; side of propodeum slightly shiny and roughened between obscure, contiguous to sub-contiguous, fine punctures.

Anterior face of procoxa with abundant long, erect, plumose hairs; without apical process. Pro-basitarsus slender and simple, without mastigion; second protarsal segment about one-third as long as first, asymmetrical; last protarsal segment distinctly shorter than first.

Metasomal terga 1-4 shiny, but not polished between very irregularly spaced fine to moderate punctures; tergum 5 similar but subcontiguously punctate; tergum 6 similar but contiguously punctate, carina bilobate, apical margin without lateral or submedian teeth or angles. Exposed sterna slightly to moderately shiny between mostly subcontiguous, fine to moderate punctures.

Pilosity erect, mostly white and conspicuously plumose; long, brownish to blackish hairs abundant on clypeus, frons and vertex, posterior one-third of mesoscutum and scutellum. Discs of metasomal terga 2-5 with sparse, very short, suberect brownish hairs; tergum 6 with short, appressed, plumose, white hairs across base and in depression basad of transverse carina; sternum 3 mostly concealed by dense, appressed, white, plumose hairs. Hairs along posterior margins of pro- and mesobasitarsi (Fig. 26) sparse and not forming a definite fringe.

Color of head and body blackish, but tergum 6 and sterna 2-3 mostly light ferruginous; appendages brownish, underside of flagellum and tarsi ferruginous. Wings clear, veins and stigma light to medium brown.

Scientific source:

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FamilyScientific name @ source (records)
Fabaceae  Andira inermis @ BBSL__BERK (1)
_  Withheld @ BBSL__YOSE (3); BBSL (5)

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Updated: 2019-10-15 08:46:32 gmt
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