44 Psyche [March-June 
One can assume, I think, that there was a certain point in 
time when both Americas were entirely devoid of Plebejince 
but were on the very eve of receiving an invasion of them from 
Asia where they had been already evolved. Going back still 
further, a modern taxonomist straddling a Wellsian time ma- 
chine with the purpose of exploring the Cenozoic era in a “down- 
ward” direction would reach a point — presumably in the early 
Miocene — where he still might find Asiatic butterflies classi- 
fiable on modern structural grounds as Lycaenids, but would 
not be able to discover among them anything definitely referable 
to the structural group he now diagnoses as Plebejince. On his 
return journey, however, he would notice at some point a con- 
fuse adumbration, then a tentative “fade-in” of familiar shapes 
(among other, gradually vanishing ones) and at last would find 
ChiladesAike and Aricia - like and Lycceides - like structures in 
the Palaearctic region. 
It is impossible to imagine the exact routes these forms took 
to reach Chile, and I have no wish to speculate on the details of 
their progress, beyond suggesting that throughout the evolution 
of Lycoenidoe no two species ever became differentiated from 
each other at the same time in the same habitat ( sensu stricto), 
and that the arrival of Plebejince in South America preceded the 
arrival in North America (and differentiation from Old World 
ancestors) of the genera Icaricia and Plebulina (and of the spe- 
cies Pie be jus scepiolus ) while the latter event in its turn pre- 
ceded the invasion of North America by holarctic species which 
came in the following sequence: Lycceides argyrognomon (sub- 
sequently split), Agriades glandon , Vacciniina optilete. It is to 
be noted that only those Plebejince which breed freely in the far 
north of Eurasia (besides enjoying an enormous distribution in 
other, mainly alpine regions) are common to both Eurasia and 
America. 
In regard to certain Lycaenids of other subfamilies, such as 
the holotropical Zizula gaika Trimen and the South African and 
American genus Brephidium , the difficulty of making them take 
the Bering Strait route is very great, but in the case of Plebejince , 
the discontinuity in distribution is not so disconcerting, and I 
find it easier to give a friendly little push to some of the forms 
and hang my distributional horseshoes on the nail of Nome 
rather than postulate transoceanic land-bridges in other parts 
of the world. 
