H. (Maximegachile), Guiglia and Pasteels, 1961

Praz, Christophe J., 2017, Subgeneric classification and biology of the leafcutter and dauber bees (genus Megachile Latreille) of the western Palearctic (Hymenoptera, Apoidea, Megachilidae), Journal of Hymenoptera Research 55, pp. 1-54 : 15-16

Subgenus Maximegachile Guiglia and Pasteels, 1961

Diagnosis and description.

This species-poor, group 2 subgenus is probably represented in the Palearctic by one conspicuous species that is well characterized in the key. In both sexes, Maximegachile consists of large, elongate bees with a typical vestiture pattern: hairs are predominantly black except snow white on the propodeum, on T1 and the basal part of T2. No other Palearctic species has such a vestiture pattern. Females: In addition, females have an elongate, 3-toothed mandible, a modified clypeus and a strong hypostomal tooth (Fig. 17 ). Males: The males are characterized by the absence of both front coxal spine and inferior mandibular projection, by the bilobed carina of T6 and the strong preoccipital carina (see additional comments to the male morphology below).

Species composition.

Two species have been mentioned for the Palearctic region and for the Arabian Peninsula: Pasteels (1979) mentions Megachile maxillosa Guérin-Méneville, 1845 from the Arabian Peninsula and describes M. esseniensis (Pasteels, 1979) from a single male collected in Southern Israel. Based on the examination of numerous specimens of M. maxillosa from Africa, it seems that M. maxillosa occurs as two distinct morphs in the male sex: a large morph (body length approximately 20 mm) with clypeus entirely glabrous and covered by coarse punctures on its disc; and a smaller morph (body length approximately 15 mm) with clypeus covered by dense vestiture at least apically and with finer punctures. A similar conclusion seems to have been reached by Eardley (2012: 26), who mentions that the lower clypeus is "densely pubescent (naked in very large specimens)". I have seen both morphs from the Arabian Peninsula but the limited material that I have seen from Israel were of the small morph, which corresponds to the description of M. esseniensis. For now, I thus place M. esseniensis as a junior synonym of M. maxillosa (syn. n.), in line with the treatment of M. maxillosa in Africa, and consequently I recognize only one species in the Palearctic region.

Biology.

Gess and Roosenschoon (2017) provide a description of the nesting biology of Megachile maxillosa in the United Arab Emirates. Nests of this species were found in trap nests. Entire cells were built using a mixture of sand and resin and the completed nests were closed with a plug of sand and resin. According to Gess and Gess (2003), the same species visits plants from various families but shows a preference for the Fabaceae, notably Crotalaria, in South Africa and Namibia.

Figures

Figures 16 - 23. Female clypeus and mandibles, front view. 16 Megachile (Creightonella) amabilis 17 M. (Maximegachile) maxillosa; the white line indicates the hypostomal tooth 18 M. (Callomegachile) sculpturalis 19 M. (Chalicodoma) hungarica 20 M. (Pseudomegachile) ericetorum 21 M. (Pseudomegachile) incana 22 M. (Pseudomegachile) sp. aff. incana 23 M. (Pseudomegachile) foersteri.