An interesting old book, 512 pages. Available as a free download from this web page (PDF is 33MB). I don't know, but I get the feeling it may be a bit of a "classic". A biographical summary on the author appears here.

Written as the thesis for a D.Sc. degree from University of Montreal in 1933. A good deal of the taxonomy & nomenclature is doubtlessly out-of-date, yet still useful as a resource on NA diptera (as understood 75 years ago).