Adults of Pale Flycatcher (above) and African Green-pigeon (below)
<bdi><a href="https://en.wikipedia.org/wiki/en:John_Gerrard_Keulemans" class="extiw" title="w:en:John Gerrard Keulemans"><span title="Dutch bird artist (1842-1912)">John Gerrard Keulemans</span></a>
</bdi>
1873
<i>Proceedings of the Zoological Society of London</i> (<a rel="nofollow" class="external text" href="https://archive.org/details/proceedingsofgen73zool">vol. 1873</a>, <a rel="nofollow" class="external text" href="https://archive.org/stream/proceedingsofgen73zool#page/n852/mode/1up">plate LVIII</a>)