Originally Posted by
hkmoths
Technically, these two terms have no taxonomic standing whatsoever. It is a convenient grouping that separates the more primitive families from the more recently evolved families, the dividing line generally falling at the Pyraloidea (considered microleps, though given "honorary" macrolep status as in many cases they are larger than a good number of "macros", such as the smaller lithosiines, eublemmines, most eustrotiines, Micronoctuidae and most eupitheciines). The Hepialoidea, Zygaenoidea and Cossoidea are also primitive taxa that would fall under the microlep group, though most moth-ers regard them as honorary macros as well. There are so many exceptions, that in reality I think it is confusing to keep using the macro / micro split.
cheers, Roger.