MOTHS AND THEIR CLASSIFICATION. 295 
collateral affinity with the T’rypanide, traceable to their common 
descent. The rather confusing cross-relationships between these 
several families are characteristic of little-specialized forms ; it 
is as if one had to disentangle a network of small divaricating 
twigs close to the stem, whilst the course of the larger branches 
is comparatively easy to trace. 
The Pyralidina are commonly distinguishable from the other 
groups already mentioned by the structure of vein 8 of the hind 
wings, which is brought down so as to closely approach or 
anastomose with vein 7 beyond the cell. Another character 
almost constant throughout the group is the stalking of veins 8 
and 9 of the fore wings; it is quite constant in most of the 
families, but in the mainly tropical family T’hyridide these veins 
are more usually separate; we may therefore with considerable 
probability regard the Thyridide as ancestral. Finding further 
that they nearly approach the Heterogeneide, both structurally 
and superficially, whilst the other families are of a peculiar type 
which is remote from anything else, we shall be justified in 
looking to the Heterogeneide as the origin of the group. The 
mutual relations of the nine families composing this extensive 
division need not be discussed here in the main; but the case of 
the Pterophoride may be mentioned. These curious insects, the 
well-known ‘“‘ plume-moths,”’ usually have the wings very narrow, 
and split into two or three feather-like lobes ; hence the neura- 
tion tends to be much degraded for want of room, but in the 
earliest forms (and recognizing the transition afforded by the 
small Australian family Jineodide) it approaches the Pyralid 
type; with which also the unusually long and slender legs, the 
structure of the head, and the larval appearance and habits are 
also in accordance. The Orneodide (in which each wing is split 
into six plumes) can be traced to the same source. 
Coming now to the groups which have vein 1c of the hind 
wings constantly absent, it will be convenient to study first the 
Papilionina, generally termed “‘ butterflies.’” Notwithstanding 
the amount of attention bestowed on this attractive group, little 
has been written as to its origin. It is characterized by the 
clubbed antenne, and absence of the frenulum, both these features 
being found in other cases but not in combination. As it falls 
into two sections, of which one (Hesperiade) has all the veins of 
