premolt
noun
pre·molt ˌprē-ˈmōlt 
variants or less commonly pre-molt
: the period before an animal molts its skin, exoskeleton, shell, etc.
Secretion of a crustacean's new exoskeleton begins during premolt while the animal is still stuffed inside the old one, filling available space to capacity.
Mark W. Denny and Steven Dean Gaines
Mark W. Denny and Steven Dean Gaines premolt adjective
or less commonly pre-molt
the premolt phase
premolt tarantulas
Word History
First Known Use
1947, in the meaning defined above