To whom it may concern:
 
I recently visited Puerto Lobos in Northern Sonora Mexico.  While on the
dunes near the ocean I observed a bee building a tunnel in the sand.  I
believe it is Hemesia (=Centris?) sp.  If anyone is interested in knowing
about the behavior I observed or has any suggestions as to how to locate
detailed info on this nest?/tunnel building behavior please let me know.
 
Harold Greeney
Dept. of Entomology
University of Arizona