Megachile sidalceae Cockerell 1897

Megachile (Pseudocentron) sidalceae Cockerell

This is a common, widespread, polylectic desert species, ranging from Texas through New Mexico and Arizona to northern Mexico and southern California. Butler (1965) states that this is the most abundant species of Megachile in Arizona and records it from a wide variety of desert plants, including Larrea, but without further data as to locality, sex, or pollen collecting. Females bearing a few grains of pollen were taken by Timberlake from Larrea at Tombstone, Arizona, 13 August 1940, and we have found them actively collecting Larrea pollen in the San Simon Valley of Arizona and New Mexico and elsewhere. The flight period recorded by Butler (1965) ranges from 1 March to 2 October.