126 
Psyche 
June- August 
mention of them above, — the sub-median as is reduced to a very 
short nervure rejoining the cubital, or perhaps as is more fre- 
quently the case, it aborts completely. What is called the median 
in the Pterygota (M^, Mb M^) is then really our own median, 
that is to say the upper anterior branch of the third nervure 
of the first group, and there is no change in the terminology. 
As for the Endoblastic Pterygota (Subulicornia and Rhyn- 
chota) more primitive than the Ecoblastic forms, it is entirely 
otherwise. Here the neuration is complete, or rather if the 
longitudinal nervures disappear it is never the sub-median alone, 
but very often the anterior median and also the anterior cubital, 
the narrowing of the wing ordinarily involving the spaces ad- 
jacent to the sub-median. This I shall have to show by palaB- 
ontology, for the ontogeny of living forms not only has been in- 
sufficient to show this peculiarity, but has at the same time led 
zoologists to form totally erroneous homologies. 
It is in the Ephemeroptera of the group Spilapteridse from 
the coal measures that we meet with the most complete neuration; 
this suits our scheme completely (e. g. Lamproptilia Ch. Brongn.) 
in certain genera, however, the anterior median and anterior 
cubital may be simple; that is, not branched. 
Everyone agrees in considering the Stephanian genus 
Triplosoha Handl. (Blanchardia Ch. Brongn.), type of the 
Protephemeroidea, as the precursor of the real Ephemeroidea, 
which are found already in the Permian; the neuration is the 
same as that of the Spilapteridse, in which the anterior median 
and cubital are represented by a simple nervure (e. g., Apopappus 
Handl.); but there are adventitious sectors in the sub-radial, 
sub-median, and sub-cubital spaces; the sub-median is simply 
forked, and between its branches is an adventitious sector.^ 
Now if we compare the wing of the Ephemeroids of the 
Permian, Secondary, Tertiary and the present day to that of 
Triplosoba, the configuration and connections show at once 
that the lower nervures considered by Comstock as and 
with the adventitious sectors between, correspond to Sr^ and 
Sr^ of Triplosoba, that is to say, the sector of the radial has been 
wrongly considered a branch of the median, because of the fact 
