These were originally placed in the Xeromegachile.
As the older genus name suggests, they are common in xeric areas. In Florida, they are most likely to be found in sandhills, scrub, and coastal dunes. Several species are oligolectic on particular species of plants. In comparison to the other subgenera of Megachile, they tend to be relatively restricted in season of flight, perhaps related to their relative specialization on certain flowers.
Key to females of Megachiloides
Lateral ocelli much nearer eyes than to edge of vertex; pubescence of sixth tergum largely appressed, the erect hairs basal, short and inconspicuous....M. deflexa
Lateral ocelli subequally distant from eyes and edge of vertex, or nearer the vertex; or pubescence of sixth tergum erect and conspicuous....2
Clypeal margin minutely denticulate or tuberculate....3
Clypeal margin entire....4
Punctures fine and close in center of mesonotum, minute and crowded on scutellum; scopa on fifth sternum with few if any black hairs....M. integra
Punctures more coarse in center of mesonotum, separated by more than their own width; punctures on scutellum fine and close, but distinct, not crowded except anteriorly;
scopa on fifth sternum black along posterior margin....M.
brimleyi
Sixth tergum in profile with no erect or suberect hairs visible, the pubescence very short and closely appressed....M. rubi
Sixth tergum in profile with at least suberect hairs visible....M.
integrella
Key to males of Megachilioides
Front metatarsi simple, neither excavated nor dilated....2
Front metatarsi more or less dilated, usually with colors other than black,
and more or less excavated on the anterior margin....3.
Front tarsi yellowish, contrasting with the black or piceous mid and hind
tarsi....M. integrella
Front tarsi not contrasting with the others, all black, piceous, or
ferruginous....M. deflexa
Front coxal spines broadly spatulate, almost triangular, robust....M.
brimleyi
Front coxal spines more slender and spine-like....4
Seventh tergum broadly rounded or subtriangular....5
Seventh tergum terminated by a quite definite spine-like median protuberance....M. rubi
Front metatarsi broadly dilated, equaling their tibiae in width; carina of sixth tergum broadly rounded and entire....M. integra
Front metatarsi relatively slender, distinctly narrower than their tibiae;
carina of sixth tergum broadly rounded, but the margin irregularly crenulate....M.
brimleyi
Note that M. brimleyi males come out twice in the key depending on the nature of their coxal spines.
