254 Psyche [December 
pairs of wings is similar. In comparing this drawing with the 
two photographs it will be seen that upon all those parts of the 
wings where the veins are present in a normal form, the markings 
are also normal. This is shown most clearly upon the base of the 
underside of the hind wings. All those parts of the wings, how- 
ever, from which the venation is absent, are aberratively modified, 
the modification increasing as we pass towards the border of the 
wings. In anormal cybele wing, the black, yellow and silver mark- 
ings are separated in more or less distinct isolated spots and points 
in consequence of the venation, while in the specimen under 
consideration all the rows of spots fuse to form complete bands 
on the parts where the venation is absent. The drawing and the 
photographs show that the form must have been produced in the 
manner just described. Moreover, the abnormal shape of the 
wings may also be traced to the partly missing venation, as the 
wings, of course, were arrested in their development on those 
parts which had no complete veins. 
This examination also explains why Mr. Bartsch captured 
damaged specimens, since a butterfly, which lacks almost every 
vein beyond the middle portion of the wings, is inevitably liable 
to the danger of injuring its wings upon its first attempt to fly, 
because it exposes to the resistance of the air a large part of the 
surface of its wings which is devoid of every support. If the 
butterfly is struck by a gust of wind, or its wings occasionally 
strike against branches or leaves, the injury to the specimen will 
soon be complete. Our specimen, which was restored only after 
considerable careful work, had suffered most from a damage of 
the fore wings. 
According to Mr. Bartsch’s statements, the flight of this form 
differs considerably from the flight of the normal Argynnis cybele 
which occurs in large numbers in the same locality. He says it 
has a quick but more wavering flight, and that any flying specimen 
of the aberration can be readily noticed. The fact that in a 
single day in 1907 Mr. Bartsch caught three specimens of this 
form, induced me to try my luck during the past summer in the 
same locality. But on both days when I began to collect there 
the weather was so unfavorable that Lepidoptera would not fly. 
Mr. Bartsch was more fortunate, as he succeeded in capturing 
another specimen of the same form in the same locality this year, 
