46 (July, 
be referred to as remnants of this age. The absence of some, such as 
Parnassius Apollo, for example, is as notable as the presence of others. 
Curiously enough, there is not a single butterfly common to the British 
Isles and Iceland, though there seems no reason why Colias Paleno and 
C. Phiconome, at least, should not be found with us. The genus Chionobas 
has reached America from Europe evidently by this path, since Chiono- 
bas Jutta has occurred in the neighbourhood of Quebec, from whence I 
have received specimens: it is still an Icelandic insect, as also an inhabi- 
tant of the Scandinavian promontory. Orymodes exulis and Plutella 
Dalella are indeed common to Iceland and the British Isles, but the 
latter occurs also on the mainland of the continent. There is one plant, — 
Arenaria norvegica, which is, I believe, not met with on the continent, 
and yet is found at Unst, in Shetland, but as far as the Lepidoptera are 
coucerned there is no evidence of any Scandinavian migration; the 
names of some beetles, such as Dytiscus lapponicus, would seem to indi- 
cate otherwise ; whether this be a fact I must leave, however, to the 
coleopterists.* 
The absence of ELrebie from the Welsh mountains must haye some 
significance,—though it is difficult to say what. 
2. Migrants of a warmer epoch subsequent to the glacial period. 
Our Islands, bathed by the gulf-stream, on the western side especi- 
ally, have winters far less severe than those of the northern half of 
central Europe; insects will therefore live with us which cannot bear the 
cold of these sterner seasons, yet for them to have reached us by migra- 
tion must have required a time of more general warmth than the pre- 
sent. 
Examples amongst the larger Lepidoptera of this group are rare, 
yet Lithosia caniola and Tapinostola Bondii may be quoted as marked 
instances ; perhaps Phlogophora empyrea, and Plusia Ni, may also belong 
to this category ; amongst the lesser Lepidoptera, Dasycera sulphurella, 
Elachista rufo-cinerea, and Lithocolletis messaniella, give us good illus- 
trations. It must be remembered that it does not follow that at this 
period of migration all the insects which came to England were of this 
delicate constitution, cotemporaneously with them many of our more 
hardy insects came. The excellent paper by Mr. Barrett, in the Feb- 
ruary number of this magazine, on the entomology of Brandon, shows 
that here we have, as it were, a leaf out of an old black-letter book still 
preserved for us, and that we can read in it what the inhabitants of a 
sandy coast on the eastern shore of England then were; some like those 
- D. lapponicus, recorded here from Inverness-shire, the Island of Mull, and Donegal, is found 
in Lapland, Sweden, Siberia, the Ost-see coast of North Germany (Eutin, Stettin), and Berlin ; 
also in the extreme south-east of France (Dep. of Basses Alpes, Barcelonnette and Col de Lauza- 
nier).—E. C. R. 
