Photomicrographs of the proboscises of Danaus plexippus (monarch butterfly, Nymphalidae) and Dyseriocrania griseocapitella (Eriocraniidae), showing that physical features of the proboscis promoting capillarity were present in early (eriocraniid) and derived (monarch) lineages. (a) Coiled proboscis of monarch. (b) Series of X-ray tomography cross sections of monarch proboscis at distances (left to right) of 261.75, 139.50, 43.50 and 6.75 µm from the extreme apex, showing dorsal legulae (dl), ventral legulae (vl), food canal (fc) and absence of an apical straw-like opening. (c) Apex of single galea of monarch proboscis with enlarged dorsal legulae and inter-legular spaces. (d) Food canal of monarch proboscis showing annulations that probably aid capillarity. (e) Apex of single galea of the proboscis of D. griseocapitella, with enlarged dorsal legulae and inter-legular spaces. (f) Food canal of D. griseocapitella with plate-like grooves that might aid capillarity. (g) Close-up image of food canal of D. griseocapitella showing smaller striations, in addition to deeper annulations, that might facilitate capillarity.