1907.] 33 



different constitution of the moths, suggests that there is some effective 

 segregation of the two colonies from each other. By any direct route 

 they are a mile and a half apart, by some long roundabout way they 

 may be still further, but for all 1 know may be in more immediate 

 relationship to each other. The picture I frame for myself of them 

 is that the hill form desires to be entirely dark, the shore form to be 

 entirely light, but that they are not separated from each other strictly 

 enough to allow this tendency its full force, but the shore form affects 

 that on the hills and keeps it more or less pale, whilst in return it 

 affords material for producing the smaller proportion of dark forms 

 that occur at La Plage. It is not, however, necessary to assume 

 that the tendency at either place would, if undisturbed, produce a 

 pure dark or light race. At the same time, I think the shox'e form 

 left to itself would be light, but the hill form w^ould not be entirely 

 dark, not at any rate whilst the pale form is still probably entrenched 

 in a vigorous heredity. 



A tolerably coherent picture results from taking this view, in 

 connection with my hypothesis of recent immigration, and combining 

 therewith a careful analysis of Milliere's report of how and where he 

 found his larva;. The little detail given by Milliere was passed over 

 by me as a mei-e gossiping account of how he met with the larva ; it 

 may have been so meant by Milliere himself. It is, how^ever, very 

 clear and lucid, and tits in admirably with the other facts to support 

 the hypothesis of immigration. He says — 



" In April, 1865, I pursued Entomology in the neighbourhood of 

 Hyeres. In exploring places near this town I was struck by the 

 quantity of Asphodclus ramosus {= micro carp us) spread over all parts 

 of the country, but chiefly on the stony hills when warmly exposed. 

 This lily, whose appearance was a novelty to me, interested me in the 

 most lively way. It exhibited tufts of leaves, long and slender and of 

 a splendid green, from the middle of which rose a thin, branched stem, 

 ending in a large spike of white and purple rayed flowers. Such was 

 the Asphodel as I saw it under the beautiful skies of Provence, amongst 

 a flora that seemed untouched by any winter. I suspected that some 

 larvse ought to be found on this green, healthy and strong plant. I 

 searched for many an hour without result." 



This is the item which I think important. Having, though fifty 

 years later approached the country round Hyeres, in much the same 

 spirit as did Milliere himself, I entertain no doubt that the district in 

 which he made this vain search was on the Maurettes, the low hills 



