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in the two orders, as is shown by the median longitudinal bars or 
striae in Phryganea grandis and different species of Cossus. 
4. The relation of pattern in fore- and hindwing. 
In the two orders the patterns of fore- and hindwing are often 
extremely different, the former showing a rich pattern, while the 
upper surface of the hindwing often presents a uniform aspect. Yet 
on closer inspection the latter likewise shows traces of a pattern, 
similar to that of the forewing and either restricted to a few spaces, 
or spread over the whole or nearly the whole wing-surface, but 
only faintly indicated. 
This remarkable condition, exhibited so well by Cossus cossus, 
shows itself no less clearly in our Phryganids. 
The likeness between certain moths and a number of Phryganids 
may indeed be called striking; the wing of the former looking like a 
copy of that of the latter. Yet a difference — seemingly an impor- 
tant one — exists: in moths the colour is located in the seales, in 
Trichoptera on the contrary the wing-membrane is the bearer of the 
pattern. This difference however is not really so important as it 
looks at first sight. For in Trichoptera, not only the wing-mem- 
brane, but also the hairs which are spread over it, are pigmented, 
either in a light or dark hue, according to their being inplanted on 
a lighter or deeper tinged wing-part. Therefore we are justified in 
saying, that the hairy covering of the wings in Trichoptera and the 
scaly coat in Lepidoptera possess colour-designs which often corre- 
spond down to the minutest details. Now as we undoubtedly may 
consider scales to be transformed hairs, the difference is reduced to 
very slight dimensions. : 
This great similarity between the two orders, so remarkable in 
itself, moreover justifies certain important phylogenetic conclusions. 
Before mentioning these however, it is desirable to consider which 
markings should be regarded as the most primitive in Lepidoptera. 
by different observations | have come to the conclusion, that the 
system of the internervural transverse stripes should be considered 
as such. 
These observations which | have to describe fully in a paper 
that will be published in a few months, are as follows: 
1. This pattern of internervural stripes occurs in a great number 
of cases in the more primitive families; especially in Cossids, but 
no less in Micropterygids and a few Hepialids e. g. the newly 
„discovered Sumatran Phassus niger VAN Ecker, Dalaca assa, Zelotypia 
stacy, ete. 
