A good deal of information about Beltran can be found here, here and here.
I find it interesting that Beltran is quoted in the second link above as follows: "Lips, for Beltran Masses, were the only way to tell the true character of his sitters, as he explained to the Los Angeles Examiner in 1925, 'eyes may lie – lips never!'". A different perspective than most artists would have, but use it as a guide for viewing the images below.
This is the earliest of his works that I noticed on the Internet. He soon abandoned this Neoimpressionist style.
Now for three similarly posed paintings...
Carmen Tortóla Valencia is said to be the subject.
The famously extravagant Casati is said not to have paid for this portrait.
Beltran painted many well-connected subjects.
Beltran spent some time in Hollywood in the 1920s.
Venice was a favorite setting for Beltran. Stunning portrait, this.
Wife of the famous Chinese politician and diplomat.
Note the blue background in this and other images. It became associated with Beltran.
Beltran made a number of paintings of nude or partly nude women that you ought to be able to find via Google or Bing.