This organ is termed the tongue by Mr. Meyrick. As many mandibulate insects possess a true tongue, and the proboscis of the Lepidoptera is not homologous with the tongue, but with the maxillæ, I think the term is very misleading.
For the examination of the wings taken from dried specimens, I have found that immersion in methylated spirits renders the veins visible after partial denudation with the camel's-hair brush. With recent specimens, however, the scales can easily be entirely removed.
I have found considerable difficulty and uncertainty in examining the neuration of undenuded specimens.
Entom. xxvi. 220.
Trans. N. Z. Inst. xxii. 218.