CtEOGKAPHICAL and seasonal variation of HEODES PHLiEAS. 169 



kept very damp, others very dry, but there is no difference in the 

 resulting butterflies. 



Amongst Mr. Pickett's captured English specimens are several that 

 are quite the form stiff'am, and one or two approach in some degree my 

 bred ones, showing that it is climate and not our race of jihlaeas that 

 prevents eleus being a common form with us. They also show that 

 the want of suffusion in my bred specimens has nothing to do with the 

 type of the race, though whether it arises from some special cause in 

 my treatment of them, or is hereditary in the actual brood experi- 

 mented with, I cannot say. I am not dealing with aberrations, so say 

 nothing about .schniidtii, and forms named by Oberthiir and others. 



It remains to refer to the Lapland form. This is large, pale, 

 tolerably typical above, except that the black spots of the hindwing 

 are much more easily seen than in the type, and, perhaps, that the 

 blue spots are the rule, rather than, as elsewhere, the exception. 

 Beneath, however, the black spots of the underwings, and the orange 

 marginal line, are pronounced in a way that no other form approaches. 



Staudinger calls this hijiKqihlanan, Jioisd., and says that it is identical 

 with the American form. Though Scudder regards the American form 

 as abundantly distinct from the European, he does not appear to have 

 been aware of the identity of the Lapland form with the American 

 (some of my specimens agree exactly with his description of the 

 American form), whilst it is difficult to regard the Lapland form as 

 distinct from our ordinary form, though I have no specimens from 

 intermediate districts to show the gradation. I am not quite sure, but 

 I think the warm varieties have the underside of the hindwing 

 distinctly of more uniform tint and freer from spots and orange 

 marginal line than the type. I may mention that Mr. Merrifield has 

 shoAvn that the effect of a high temperature in producing dark 

 specimens of phlaeas, takes place during the pupal stage, whilst the 

 imago is maturing within it, and that warmth in an earlier pupal, and 

 in the larval, stage, has little or no effect. 



We speak of the difference between pidaeas and eleus as a seasonal 

 one. This is not strictly correct. It is an individual change due to 

 the direct action of temperature, there is no distinct alternation of 

 forms as in Araschnia levana and prorsa, or as in our English 

 Ennomids, alternatives which Merrifield found he could break 

 through only with difficulty. In JI. phlca'cui each individual is prepared 

 up to the pupal stage to take either form. How then may we arrange 

 the ordinary (i.e., not aberrational) forms oi jihlaeas (west European)'? 

 We may, with little hesitation, accept Iii/pop/dafos as a distinct 

 geographical race or subspecies. When we come to eleiis, we must, I 

 think, in the first place use the name in two senses, it is primarily the 

 name of the darkest form of p/daeas. It must also be given to the 

 southern race of pldaeas. 



The experiments of Weismann, Merrifield, Standfuss, Fischer, &c., 

 bring out apparently, that the southern races respond with much 

 greater readiness to the proper temperature stimulus that produces 

 deioi, than the central European form does. There also exists a belief 

 that the normal (cool) form of this southern race is darker than central 

 European pldueax.. In some cases this is probably true. Whether 

 essentially darker, or merely responding more easily to stimuli to 

 become darker, it has a sufficiently different constitution to be 



