The Collaborative International Dictionary of English v.0.48:

Melissyl \Me*lis"syl\, n. [Melissic +yl.] (Chem.)
   See Myricyl.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Myricyl \Myr"i*cyl\, n. [Myricin + -yl.] (Chem.)
   A hypothetical radical regarded as the essential residue of
   myricin; -- called also melissyl.
   [1913 Webster]