The statement is true & valid but caution in interpreting a field shot.
In P. bevani ,spot 3 is distinctly nearer spot 2 than spot 4 (Note spot 4 sometimes may be absent.)
http://yutaka.it-n.jp/hes/93070001.html
In B. cinnara FW spot 3 is only a little bit nearer spot 2 than spot 4, & may be appeared almost equidistant from both.
http://yutaka.it-n.jp/hes/93060001.html
TL Seow: Cheers.