The following material taken with permission from: Mitchell, T.B. 1962. Bees of the Eastern United States, Volume II. North Carolina Agricultural Experiment Station. Tech. Bul. No.152, 557 p.
Megachile is a cosmopolitan group of non-metallic, usually robust, black bees. The basal abdominal tergum is concave anteriorly, but not carinate. The posterior face of the propodeum and the metanotum are nearly perpendicular, with no dorsal pitted area. The scutellum is broad, its hind margin nearly straight, with rather large axillae which are not conspicuously protuberant and never acute. The pleura and tubercles lack carinae and the notaulices are linear. In the front wings both recurrent veins are received by the 2nd submarginal cell. The maxillary palpi are 3 segmented, while the mandibles are 3- to 5-dentate.
In the males the front coxae usually are spinose, and the front tarsi are often much dilated and modified. Tergum 6 is more or less vertical, usually with a subapical carina which forms the actual apex of the abdomen. Tergum 7 and the true apical margin of 6 are ventral in position. Sterna 1-4 commonly are exposed, 5-8 retracted and highly modified.
Typically these are leaf-cutters, the females cutting circular or oval pieces of leaves which are used as cell linings and caps. These cells are constructed in a variety of locations, many species nesting in the soil, sometimes gregariously, while others make their tunnels in rotting wood, or use borings or cavities in wood or in plant stems. One group of species, the subgenus Chelostomoides, does not cut leaves, but uses resin in the construction of the cells. This group appears to be related to other groups in other parts of the world, which have somewhat similar habits, and it is probable that these will eventually be separated from Megachile as a distinct genus.