Note:

• Published as a serial "La Masque" by "Cousin May Carleton" in the (New York) Sunday Mercury, beginning Vol. XXIV, No. 1226 (1862-07-16) --"Frank Starr's Fifteen Cent Illustrated Novels", Beadle and Adams Dime Novel Digitization Project (ulib.NIU.edu/badndp)
• Notes (quote):   Published in 1863 under title: La Masque; or, The midnight queen.   Wright III-1907. --WorldCat library record of the 1888 Dillingham edition, OCLC 3907454 (apparently from a posthumous uniform edition of Fleming's novels)
• (quote) A reprint or reworking of LA MASQUE; OR, THE MIDNIGHT QUEEN. A TALE OF ILLUSION, DELUSION, AND MYSTERY published under Fleming's pen name "Cousin May Carleton" in New York by E. A. Brady in 1863, of which no copy appears to be extant. --LWCurrey.com 151903 as of 2016-10-21 "E. A. Brady" must be Frederic(k) A. Brady, Publisher, No. 24 Ann St., New York (from contemporary newspaper advertisements; this title not found)
• Digital copy of 1888 edition at HDL, lacking original cover, states copyright 1888 by the publisher, does not mention earlier publication
• The 1902 edition gives a copyright of Beadle & Adams, 1876.

Synopsis: "Sensational historical romance set during the Great Plague of London; title character Death personified, 'La Masque' hides a fleshless skull. ..." --quoted at LWCurrey.com 151903 (above)