The image above comes from the 1894 Vermont Ancient and Accepted Scottish Rite book. It appears to be a fairly common image for the 19th degree of the AASR (“Grand Pontiff, Sublime Scot”).
Here we have the snake with more context and an explanation:
3. The ruined City of Jerusalem to which the three-headed serpent of evil is chained.
There is an interesting variation, perhaps an older version, in the Baylot manuscript, a collection of (old) degrees. There we have a three headed snake which is crushed below the rubble of an unnamed city. During the ceremony, the candidate even steps on the three heads of the snake. This scene appears to be depicted on a “Sublime Ecossais” tracing board in Maçonnerie des Hommes (1766). See here.
Also see table.
Top: The Book Of The Ancient And Accepted Scottish Rite (1884) Charles McClenachan
Bottom: A. & A. R. The intermediate Degrees 19º – 29º A.C.F. Jackson (1982)