Internet Archive ID: handbooktoorderl02kirb described at URL: https://archive.org/download/handbooktoorderl02kirb/handbooktoorderl02kirb.pdf determination method...
recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:A_hand-book_to_the_order_Lepidoptera_(IA_handbooktoorderl02kirb_0).pdf...