Tj. Simonsen, The wing vestiture of the non-ditrysian Lepidoptera. (Insecta). Comparative morphology and phylogenetic implications, ACT ZOOL, 82(4), 2001, pp. 275-298
The ultrastructure of the dorsal forewing vestiture in exemplars of all fam
ily group taxa of non-ditrysian Lepidoptera is examined, and the evolutiona
ry implications at family level and above are discussed. Wing-scale termino
logy is reviewed. Three different types of bilayer wing-scale covering are
recognized; only a few groups have a single-layer wing-scale covering. The
general scale arrangement is random, but a few taxa have clustered scale ar
rangements and scattered heteroneurans have scales arranged in transverse r
ows. Cross ribs are present in all taxa, but only as vestiges in eriocranii
d cover scales. Ridge dimorphism is widespread in Neolepidoptera. Surprisin
gly, ridges and cross ribs on the adwing scale surface are of general occur
rence in Neopseustidae and Hepialidae, and are even found on parts of the g
round scales of many other Neolepidoptera. Morphological evidence strongly
indicates that the fused wing-scale types found in non-Coelolepidan Lepidop
tera and Neolepidoptera are independently evolved, as evidenced from the pr
esence of vestigial perforations. Absence of perforations is not infallible
evidence that a scale is solid. Microtrichia are independently reduced in
a number of taxa and probably re-evolved in at least higher nepticulids. Wi
ng vestiture and scale characters indicate that Tischerioidea may be the si
ster group of Ditrysia.