304 C. O. WHITMAN. 
papille, then we may say that the dark brown stripes cor- 
respond to the dark borders of the yellow stripes. But in the 
typical specimen there are five yellow stripes and twice as 
many dark borders ; how then can these ten borders be repre- 
sented by six dark stripes? Fig. 10 is an enlarged pencil 
sketch showing accurately the distribution of the dark pig- 
ment of fig. 18. From this figure it will be seen that each of 
the dark stripes appears to be composed of two parallel halves 
that have imperfectly blended, leaving here and there evidences 
of their duplicity. This is especially manifest in the two 
broader median stripes, and but little less so in the external 
lateral stripes. These six stripes may then be said to repre- 
sent twelve dark borders, of which ten ordinarily accompany 
the five yellow stripes, and two form the inner borders of the 
yellow margins. 7 
Now, there are three ways in which the dark borders could 
be made to unite in pairs. First, the widening of the yellow 
stripes would bring together the six pairs of adjacent bor- 
ders ; second, the widening of the borders themselves, allowing 
that the yellow stripes persist, would accomplish the same 
result; third, the obliteration of the yellow stripes would bring 
together the two borders of each stripe. These three cases 
are all more or less perfectly represented in the figures of this 
plate. 
In fig. 18 it is the widening of the yellow stripes and the 
yellow margins that accounts for the arrangement of the dark 
pigment. That the dusky yellow area enclosed between the 
two median dark stripes corresponds to the median yellow 
stripe of the typically coloured specimen, is made sufficiently 
evident both by its position and by the manner in which it 
terminates on the cephalic lobe (fig. 18), and on the aceta- 
bulum (fig. 10). If this correspondence be conceded, a parallel 
correspondence must also be claimed for the two lateral dusky 
yellow areas of each side. 
In fig. 11, which represents a portion of fig. 12 magnified 
four diameters, we have an illustration of the second case, in 
which there are six dark brown stripes formed, not by the 
