1900. ] GROTE—THE DESCENT OF THE PIERIDS. 9 
des have been developed from the same phyletic stem which finally 
produced the Pierids and Hesperiades. 
If the alternative conclusion be adopted which I have suggested, 
that the so-called ‘‘ precostal spur ’’ is really homologous with the 
‘‘ humeral veins’’ of the Lachneids, we must seek for the origin of 
the Hesperiades in common with that branch of Dr. Dyar’s Bom- 
bycides in which it is developed, and probably simultaneously from 
antecedent Tineid types. This would seem to weaken the prob- 
ability, suggested by Sir George Hampson’s phylogeny, that they 
are derived from forms which have not developed the structure, 
unless we assume the humeral spurs to be characters of convergence. 
This humeral vein, which I shall call in the progress of this paper 
the ‘‘ humeral spur,’’ is single in the Hesperiades, and may be here 
a survival, others having perhaps disappeared. This survival itself 
gradually fades away ; in Zervzas it isa mere knob, in WVatha/is it 
has nearly vanished. ~ 
The primitive Hesperiad had probably a wing in which the 
veins and branches were all separate, the base of the median sys- 
tem more or less fully developed and with the first anal existing. 
The second median was central. The cubital cross-vein was present. 
The fork of the second anal was possibly expanded into a longitu- 
dinal vein connecting with second anal by across-vein. The prim- 
itive Papilionid was probably propinquitous, having most features 
in common, but the third anal was longer and unconnected, and 
there are indications from the position of the second median that 
it was not’ central as in the primitive Hesperiad from the different 
shape of the discal cell. On the hind wings the primitive Hespe- 
riad would have lost the three outer branches of the radius, but the 
first would be present, closing the subcostal cell as in the Sphingi- 
dz. On the costal region of primaries the costal vein might have 
been functional, but it had probably already left the secondaries. 
Instead there might have been a greater development of humeral 
spurs. 
It will accord best with the paleontological record if we assume 
an early and comparatively quick evolution for the diurnals, and as 
in these are included the Papilonides we must finally say a word as 
to their presumed origin. 
I have recorded elsewhere my search for the short downwardly 
curved third anal vein of the Papilionides’ primary wing. Mr. 
Meyrick having figured it in the Geometridz, I sought for but 
