( vii ) 
Southern range— 35° N. lat. 
'A. thetis into Mauretania (withoiit 
A. coridon). 
A. coridon into Syria (without A. 
I. thetis). 
(Both sjiecies occur on the north 
shores of the Mediterranean, in 
Spain, Italy, Greece and Asia 
Minor.) 
Eastern range —50° E. long.— Both species in Persia. 
(A, thetis the Ufa dist. 56° N. lat., 55° E. 
long. 
A. coridon the Orenburg dist. 55° N. lat., 
55°-59° E. long. 
f A. thetis —56° N. lat. in the Ufa dist. 
{A. coridon —57° N. lat. in the "Viatka dist. 
(Both speeies then fall to 53° N. lat. in Northern 
Germany, A. thetis extending into Denmark 
(without A. coridon), both pass into Belgium 
and then into England to about 52° N. lat. {A. 
thetis) and 53° N. lat. {A. ooridon).) 
Western range. —The Atlantic littoral for both species, in England, 
France and Spain. 
North-eastern range. 
Northern range. 
One quite appreciates the value of a “physiological factor” 
as an effective “ isolation ” barrier. This cannot arise over 
the foodplant which, in Britain, and certainly in most con¬ 
tinental localities is restricted to Hijr^jocrejns comosa. Zeller 
has recorded {Stett. Ent. Ztg.) Coronilla vciria as the foodplant 
of A. coridon, but Krodel asserts {Allg. Zeits. far Ent.) that 
larvae of A. coridon that he had, prefeimed to starve rather than 
eat G. varia, although feeding ravenously again as soon as ff. 
comosa was obtainable. The larva of A. thetis, too, is reported 
as refusing to feed on anything but H. comosa. 
We have already dealt with the long lists of reputed food- 
plants of these species (possibly nearly all erroneous) in A 
Natural History of the British Butterflies, vols. iii and iv. 
But two “isolating” factors occur in the habits of the 
species :— 
(1) A. thetis hybernates as larva in the 3rd instar. A. coridon hyber- 
nates as fully-formed larva inside the eggshell, and does not hatch till 
about end of March. 
(2) A. thetis is throughout its whole range doirble-brooded, not failing 
in its most northern habitats. A. coridon is [with the exception of a 
limited area on the Riviera, and possibly in some lowlying (coast) districts 
of Italy and Spain] single-brooded. 
The result of these factors is such that the single brood of 
A. coridon (July-September), roughly falls between the two 
broods of A. thetis (May-June and August-October), with 
