SEASONAL POLYMORPHISM. 141 
date of capture, answering to the first generation of the latter, would 
strongly suggest its belonging to it. A more accurate inspection, on 
the contrary, quite satisfies one that it is nothing but a coridon, similar 
to the Asiatic race caucasica, Led., and that it exhibits no traces of 
thetis characteristics, except the two mentioned above. It differs 
markedly in this both from the description of polonus, Z., and of 
ealydonius, Lowe (Wheeler, Butt. of Switz., p. 31); the former is 
described as having the underside of thetis, which, in Central European 
races especially, is very different indeed from that of coridon; the 
description of the underside of the latter points to the same conclusion. 
The underside of my specimen on the contrary does not differ in the 
least from that of other coridon collected higher up on the Grand 
Saléve in August. The shape of the wings and the fringes are also as 
in this species and so is the marginal black pattern of upperside, 
although, in coridon, specimens with this pattern as reduced in extent 
are scarce; the premarginal spots are quite large on both fore- and 
hindwing ; they nearly stand out completely from the narrow marginal 
streak even on the forewing and the latter extends along the neuration 
in thin sharp points. Except for the epoch of emergence, there would 
be no reason to suspect a hybrid; the existence of caucasica in the Kast. 
seems to point to a phenomenon of hypermorphism rather than to any 
other; precocious emergence supports this view. I leave it to the 
numerous and clever Lepidopterists of Geneva to find out whether 
this form is constant or frequent and to better work it out, as it 
well deserves. 
The two specimens founa by Keynes in the Pyrenees in June seem 
from his description (Hnt. fRec., xx., p. 178), to be like the 
Geneva ones. 
A stroke of luck gives me a chance of comparing the specimen 
described above with what seems to be exactly Zeller’s polonws : 
O. Querci, collecting in the Alpi Apuane (N.-W. of Tuscany) and 
precisely at Careggine (m. 1000), captured a few days ago (mid-June, 
1920) two abnormal male specimens, which were flying with no more 
than half a dozen normal 4A. thetis; no others of this species have 
been seen in that district and no coridon has, of course, appeared yet, 
its period of emergence only beginning at the end of July. These 
specimens are smaller than samsoni, corresponding to the size of thetis 
in their locality ; the wings have exactly the rounded shape of the latter 
and the underside pattern does not differ from it either: the fringes 
on the contrary are a little longer than in thetis and are also chequered 
more as in coridon ; the marginal black pattern above is fundamentally 
as in samsoni, but the narrow marginal streak gradually shades off in 
zone of sparse black scaling, mixed with the blue ground-colour which 
reaches beyond the pre-marginal black spots and on the hindwing 
vaguely shadows a series of pre-marginal lunules; thin nervural 
streaks stretch far beyond it on all the wings; the spots are large and 
shade gradually in the said blackish zone ; the ground colour is not as 
brilliant as in samsoni or caneasica, but duller and heavy, and the blue 
is of an extremely cold tinge, distinctly greenish. As Zeller’s polonns 
in the original description is said to have “on the upperside a ground 
colour combining the blue of both species (‘midway between adonis 
and corydon’), but with the marginal markings of corgdon, whilst on 
underside the colouring and marking is that of adonis,” that name 
