8 THE ENTOMOLOGIST’S RECORD. 
return to a constant type, such as takes place in phlaeas in its first genera- 
tion, is very unusual. It seems obvious that in a case of this sort the 
thought of instability must be discarded, and the hypothesis of an 
unusually high degree of “individual elasticity’ is more likely to be 
correct; this would allow the species, or one of its races, to move into 
very different surroundings without being compelled to modify itself 
for adaptation, by recurring to its “specific elasticity” (see introduction 
to Rhopalocera Palaearctica). 
That individual elasticity, if drawn too far, must issue in a phylo- 
genetic split (to use the mechanical image of the process further), and 
in the establishment of two new centres of balance, seems to be 
shown by the fact that allied genera carry on variation along the same 
line either in one direction or in the other. In this case of the Chry- 
sophanidi sexual dimorphism brings it to its extreme limits both ways 
in the male: in Thersamonia, Chrysophanus, and Heodes, the reduction 
in the extent of the dark scaling of nymotypical phlaeas is pushed to 
its total or nearly total obliteration; in the Loweia the dark suffusion 
of fuscata goes so far as to cover the whole of the wings. It will be 
noticed that the Lycaenidi vary in broad lines in an exactly parallel 
way; the Lycaena correspond roughly to Rumicia, and still better to 
Kasyapa, Moore; the Raywardia to the Thersamonia, the Aricia and the 
females of Polyommatus, Agriades, Plebeius, etc. to the male type of 
pattern of Loweia dorilis, whilst the males of the three genera last 
mentioned take up and develop to its highest degree the male 
refracting scaling which is golden in virgaureae, dispar, etc., and 
which becomes violet in hippothoé, alciphron and amphidamas, ete., 
besides the uniformly black ground colour, which is seen in ewmedon, 
and which acts as a background in thetis, icarus, etc., and gives the 
reflected light its brilliancy, thus also greatly due to extreme 
melanism. In the genus Lycaena and others the blue, on the contrary, 
is equivalent to the copper of Rwmicia and of the females of other 
Chrysophanidi, and originates from the so-called ground colour of the 
wing, so that it increases as the dark pattern diminishes in extent, in 
a way exactly inverse to that of the blue mentioned before. All this 
constitutes only one of the countless examples offered by the Lepi- 
doptera, which tend to show that variation occurs according to defi- 
nite plans ; these are seen on a lesser scale in the individual variations 
of races and species, and reappear in a magnified form when allied 
species or genera are compared to each other, besides repeating them- 
selves more or less completely and constantly in each equivalent and 
collateral branch. 
(To be continued.) 
_ The Sydney Webb Collection of British Rhopalocera. 
This famous collection, rich in aberrations, was sold at Steven’s 
Auction Rooms on the 21st October and 9th December last. 
Admittedly the collection was one of the best in private hands in the 
country, and a short description of the principal lots and prices 
‘obtained, should be of interest. The first sale commenced with 
the Piertdi and ended with the Argynnidae as far as Brenthis 
selene, a fine lot of 15 Chrysophanus dispar coming as @ finale. 
Lots comprising 1 to 8 Papilio machaon, nearly all being minor 
