34 
characterisation), but even he placed flavofasciata at the opposite end of 
them to ajjinitata, and made it (the former) lead on to luteata, &c. 
Meyrick (Trans. Ent. Soc., 1892, p. 73), improves the sequence, placing 
flavofasciata between the affinitata group and albulata; but he has 
blantliata (adaequata) separated from the rest of our genus by three 
apparently much less related species. 
P. flavofasciata is widely distributed in Europe, though it is not 
certainly known to extend much beyond. In Britain it is considered 
fairly common, but somewhat local. I have met with it in most of the 
southern localities where I have done much collecting. Like most 
geometers, it may be beaten from hedges by day, or taken on the wing 
at dusk. The larva is attached to Lychnis , though in Ireland it is said 
to have been taken on Silene inflata. Barrett (Ley. Brit., viii., p. 230) 
considers Lychnis alba (vespertina) its favourite foodplant, but at 
Sandown, where both these species and L. dioica abound, I am almost 
sure I have found it more freely in the latter, and near Brendon, 
N. Devon, where L. alba seems very rare, I have taken it only in L. dioica. 
Perizoma albulata, Schiff. ("niveata, Stph.).—This is, from the 
point of view of its variation, the most interesting species of the genus, 
having a considerably wider range of variation than any of its congeners, 
and being more or less addicted to the formation of geographical races. 
In our City of London List (Trans. City Land. Ent. Soc., x., p. 68) I 
followed Snellen in calling the species niveata, Stph., to avoid collision 
with albulata, Hfn. ( = candidata, auctt.). But it is not quite certain 
whether a change Avas necessary, as Schiffermuller’s species was erected 
as Geometra albulata and Hufnagel’s as Phalaena albulata, and I do not 
find positive proof that they have ever collided with a common generic 
name ; I think, therefore, that the familiar name should be given the 
benefit of the doubt, and would let the tAvo species stand as Perizoma 
albulata, Schiff., and Asthma albulata, Hfn. In any case, *niveata, 
Stph., is unavailable, as I find he simply used it upon an erroneous 
determination of niveata, Scop.; should a change prove necessary, 
ablutata, Ev. (Faun. Voly. Ural., p. 398), will have to be adopted— 
though probably, originally, only a slip for albulata. 
The synonymy given in Staudinger (Cat., ed. 3, p. 305), is fairly 
correct. It seems a pity that the forms griseata, Stgr., and thules, 
Weir, should be nearly lost sight of under “ var. et. ab. a., subfasciaria, 
BohAvhich is recorded as an aberration for England, Scandinaviar 
and Lapland, and merely as becoming a “ var.” in Shetland; I am 
bound to admit that the true thules form, as figured by Jenner Weir 
(Entom., xiii., pi. iv., fig. 4, 5,) is only an extreme form, and will have 
to be called “ ab.,” rather than “var.,” but both it and griseata 
certainly deserve separate entry in the Catalogue. There are consider¬ 
able obstacles in the way of an ideal scheme; for although series of, 
say, a dozen representative specimens from each of three localities 
(England, Shetland, Finmark), could easily be localised by experts, 
and Avould fully attest the existence of geographical races, yet there is 
so much variation in any given locality, that individual specimens 
Avould certainly be found in each series Avhich agreed practically Avith 
the form more prevalent in some other locality. Of course, this is 
only Avhat, to a greater or less extent, prevails everyAvhere, and bothers 
us in our attempts to make a cut-and-dried varietal system; but it is 
not ahvays nearly so manifest as in the present case—for instance, 
