388 MIMICRY IN THE COLORS OF INSECTS. 
Fedia radiata Michx., var. umbilicata (F. umbilicata Sulliv.). 
Fig. 108. Fruit (from Columbus, Ohio) ; a, side view; b, another 
side view, showing the cruciform opening caused by the ten- 
dency of the cell in the abnormal expansion of its walls to split 
along the sutures; c, cross section of the same; d, side view 
of a more mature fruit, showing a further enlargement of the 
opening into the empty cell; e, another side view. As the fruit 
of the former variety came probably from that of F. radiata, with 
two empty cells, as seen in Fig. 104, so this may have been de- 
rived, by the operation of the same cause, from that of Fig. 104¢, 
with the empty cells confluent. 5 
In view of the decided disposition toward monstrosity evident 
in Fig. 107, and the differences of the fruits iù size and shape, it 
is questionable whether F. patellaria and umbilicata are worthy to 
stand even as varieties of F. radiata; but, since no typical fruits 
of the latter haye been observed intermingled with the aberrant 
forms on the same stalk, they may for the present be i 
as such. 
MIMICRY IN THE COLORS OF INSECTS. 
BY DR. H. HAGEN. 
Havine observed that in treating of the interesting phenomen 
of mimicry, writers have used indiscriminately very different se 
tors, I shall try to give some preliminary ideas which I do not find | 
published, and which I believe will be useful in explaining W 
interesting subject. | 
It will be best to consider the color and pattern separately. 
There are three different kinds of colors: viz., colors p the . 
` by interference of light, colors of the-epidermis, and colors of 
hypodermi All three may either be wanting, Or all three, | 
_ two of them may occur together in the same place. xed 
Colors produced by interference are produced in two Cl 
‘ways; first by thin superposed lamellæ, as in the wings of D ee 
Neuroptera, ete., without any other color, as in hy aline wine® 
connected with other colors as in the scales of Entimus #0" ak 
There must be at least two superposed jamella to bring ' 
