168 PROBLEMS OF GENETICS 



Immediately north of the Pyrenees we still meet egeria exclusively, 

 and up to Poitiers at least there is no noticeable change. But 

 somewhere between Poitiers and the bottom of the Loire valley 

 at Tours, the genuine southern type comes to an end, and the 

 whole population begins at the Loire to be of an intermediate 

 type, easy to distinguish both from egeria and from egerides. As 

 to the exact condition of the species in the fifty miles separating 

 St. Savin on the Vienne from places on the Loire I have no ade- 

 quate information. I have only one small sample from there, 

 but it does contain insects both of the southern and intermediate 

 types taken on the same day, in a wood near Preuilly. Oberthur 

 also states that at Nantes the true southern form exists in com- 

 pany with the northern. From this I infer that the southern 

 form extends up the coast further than it does inland, but I 

 imagine the representative spoken of as northern would be of 

 usual Brittany or intermediate type. 



The Vienne river joins the Loire, so the true southern type 

 reaches over into the basin of the Loire. From the Loire (Tours, 

 Cormery) north to Calvados (Balleroy) only the intermediate 

 is found, so far as I know, and the same type extends over 

 Brittany. 7 In general, however, the woods near Paris have the 

 thoroughly northern type egerides, but at St. Germain-en-Laye 

 and at Etampes (Oberthur) the population approaches the 

 intermediate type. 



On the whole the intermediate type is certainly less homo- 

 geneous than either of the extremes, and females with the two 

 central spots either paler or more fulvous than the rest are not 

 uncommon, but I have never taken one on the Loire or in Brit- 

 tany which I should class with either of the extreme types. 



Before speaking of the distribution in other parts of France 

 and in Europe generally I will briefly state the results of my breed- 

 ing experiments. The work was done many years ago before 

 we had the Mendelian clue, and it is greatly to be hoped that 

 some one will find opportunities of repeating it. Crossing the 

 English and the thoroughly southern type the families produced 



7 Mr. G. Wheeler kindly showed me a series identical with this type, from 

 Guernsey, and others from near Laon. 



