LITUOSIA LUTAKELLA AND ITS VAKIPVrY, KTC. 221 



often termed by the learned pliylo<2;enetlc relationsliips, l)ecause tliey tell 

 us in unmistakable characters, more or less of the developmental 

 history of their race. It is of the pliylogenetic signiticance of the colour 

 and markings of pi/gmaeola I would speak. 



I will not theorise to-night, but just point out a few facts. You can 

 then deduce your own theories. Staudinger says of Doubleday's 

 pi/tjmacola: "Anterior wings pale greyish-yellow," and that you see 

 applies to many of my specimens. Now look carefully at my series of 

 specimens from Deal. I have divided them up in a general way into 

 batches, and you will see that a moderate pro})ortion are somewliat 

 unicolorous, pale yellowish-grey specimens m both sexes — undoubtedly 

 the true variety pijijmaenla. But coming very near to these is anotlier 

 group, with the head, thorax and wings distinctly bright yellow. Then 

 we ilnd that a few specimens are not satisfied with this but reach a 

 bright golden sororcw/a-like colour ; so that we have pale yellowish- 

 grey, brighter yellow, and golden forms in ascending sequence. Now 

 let us go down. We find specimens of a much duller greyish-yellow 

 than the first, the costa, however, remaining quite pale yellow com- 

 pared with this ground colour (a small, ill-defined Inridcola in fact). 

 Then an unicolorous leaden form (nearly all taken in the year 1888, and 

 referred to in my Melanism and Melanocliroism in British Lepidoptera), 

 whilst this leads on to the darkest specimen of all, not cpiite black, and 

 unfortunately not in excellent condition. Then I remember one of 

 our collectors telling me some years ago that he had taken one spotted 

 somewhat like mnscerda. That the characteristic coloration and mark- 

 ings of almost all our species of Lithosia should occur in this one 

 species is surely striking enough to make you wish to know more about 

 this insect, and to seek for the meaning of this variation. What is the 

 pliylogenetic significance of these facts? I told you I would not 

 theorise, I think there is no need to do so, because it would be insulting 

 to your intelligence, to suppose that you cannot read the lesson as well, 

 at least, as I can. 



Pygmaeola is variable then, and its variability probably makes it a 

 little more interesting ; but we have not done with the insect yet. 

 Pygmaeola is only a local race, it is, in the true sense of the term, only 

 a variety itself. The lesser variations then cannot be varieties, and 

 they are of coui'se not aberrations ; yet, if they are to convey a definite 

 impression to us they must be given some more or less definite value, 

 and hence scientific men call them sub-varieties of the local race 

 we know so well under the name of pygmaeola. Some of you may have 

 smiled at the thought of a sub-variety ; I trust I have made clear to 

 you that sub- varieties are existing facts and that the tenu " sub-variety " 

 is therefore a necessary one if the real scientific meanings of the varia- 

 tion of some of our species is to be worked out. 



Well, it pygmaeola is only the name of a local race of the species aiul not 

 the name of the species itself, what is the name of the latter? 3-ouask. The 

 trivial name of the species is hdarella. In the Val de i\Ioney, a branch 

 of the Val de Cogne, between Cogne and Valnontey, in full view of the 

 great and grand glacier of the Kossa Viva which faces towards Cogne, 

 and tliree or four miles only from its termination. Dr. (Jhapmau found 

 L. InlarcUa in some abundance, although I had previously taken two or 

 three specimens in the Cogne valley itself, between Silvenotre and 



