by William Swainson, Zoological Illustrations Series II… (1829)
“ The habits of the Swallow tribe are known to every one. Like the Flycatchers, they feed upon insects captured on the wing; but these insects are of so small a size, that they are swallowed during the flight of the bird. This at once accounts for Swallows not being provided with those stiff bristles, for confining the struggles of their prey, which are so essential to the Flycatchers. These latter birds frequently feed upon insects much too large to be swallowed at the moment of capture ”
