TRIASSIC INSECTS OF QUEENSLAND. 
43 
Belmontia, although this fossil stands on a side branch not very far 
removed from the main stem. It seems then that the discovery of Eoses 
again draws attention to the fundamental relationship between the 
ancestral Mecoptera and the Trichoptera and Lepidoptera, a relation- 
ship which tended to be overlooked after the discovery of Belmontia. 
Detailed comparisons between Permochorista and Eoses indeed 
show that however much the form of the wings and the general appear- 
ance may differ, there are basic features in common extending even to 
the possible relict character of a pterostigmatic area on the costal margin, 
and it seems an irresistible conclusion that Eoses and Permochorista are 
fundamentally related, and that this relationship exists because they 
had common ancestors in Permian times. 
The tentative conclusion is reached therefore that Eoses is a primi- 
tive Lepidopteron, representing a stock which had its origin in a branch 
of the order Mecoptera, from which it parted company at the end of 
the Palaeozoic or in the early Mesozoic. 
Having been so bold as to see in Eoses an early member of the 
Lepidoptera and therefore the first known Mesozoic member of the order, 
the writer is tempted to determine a tentative classification into which it 
may be placed. 
Eoses may be conceived to be related to, and to fall in the same 
suborder as, the ancestor of both the Homoneura and the Heteroneura. 
As both Comstock and Tillyard have shown, any attempt to construct 
an archetype for the Heteroneura leads inevitably to an ancestral 
Homoneurous type, and this archetype, as deduced even in the absence 
of any leads from fossil evidence, differed significantly from Eoses 
principally in the character of the bifurcate M 2 . 
For convenience it may be useful to regard this archetypic concept 
in so far as it is represented by Eoses as constituting a suborder Eoneura 
of the Lepidoptera, equal in classificatory value with the Homoneura 
and the Heteroneura. Both the Homoneura and Heteroneura may have 
been formerly derived from the Eoneura. This new classificatory concept 
must be viewed in very broad detail, and it is as well to remember that 
Eoses itself may not be a direct lineal ancestor of the later Lepidoptera, 
rather but one representative of a whole range of early Lepidoptera of 
the Eoneura, from one of which later Lepidoptera may have been derived 
by reduction and specialisation of the characters which we see in the 
Eoneura. In so far as both Homoneura and Heteroneura differ from 
the Eoneura in the absence of the bifurcate M 2 it may be that they are 
both to be derived together from a member of the Eoneura in which this 
reduction had already taken place. 
A tentative classification could be arranged as follows: — 
Order Lepidoptera. 
1. Suborder Eoneura. 
(a) Family Eosetidae. 
