A STUDY IN MASCULINE MUTABILITY. 141 



A fourth form, in which the elytra are of the normal ochreous with 

 dark apex (var. $ analis, Seid.), did not appear to be represented 

 among these specimens, but I have an example in my own collection 

 which may be referred to it, taken at Rhosneigr, in Anglesey. It 

 appears, therefore, that the whole of the forms of this insect recognized 

 as varietal liy continental authorities also occur in this country, and 

 similarly are confined to the male sex; and the question at once arises: 

 Why is this variability so specially implicit in masculinity ? What is 

 the principle which enables or induces the male organism, so much 

 more than the female, to express itself in unequal individual pigmen- 

 tation '? For that is the direction variation takes in this case. Now 

 it is obvious that even the most tentative answer to such questions as 

 these would require far more knowledge than we at present possess of 

 one of the most dilBcult questions of Biology- — the essential meaning 

 of sexuality. But before dismissing the subject as beyond our grasp, 

 a few words may be devoted to expanding it. For whether we hold 

 with that school of biologists of wbom, in this country. Prof. Geddes 

 is perhaps the chief exponent, that sex maybe expressed fundamentally 

 in terms of Energy, maleness meaning predominant Katabolisn), or 

 expenditure of energy in excess of nutrition, femaleness a predominant 

 Anabolism, or nutrition in excess of expenditure of Energy, Avhich 

 theory would imply that organisms are sexually indifferent up to a 

 certain point in their embryonic life, and that the tendency which 

 finally determines sex may depend very largely on conditions of 

 nutrition — or whether we rather adopt the view that sex is unalterably 

 determined in the fertilized ovum — this much at least we must admit, 

 that there seems to be a wider choice of alternatives, or a freer 

 response to Environment, among the cellular determinants, which 

 originate pigmentation in the male than in the female of this insect. 



And this is true, although we may interpret the facts in two ways, 

 or, at any rate, recognize that there are two quite distinct lines such 

 an interpretation might take. 



(1) We may regard these varietal forms as virtually hybrids — the 

 simple result of inheritance, partial or blended, and their colonr differ- 

 ences the expression of such inheritance, in accordance doubtless with 

 Mendelian principles, but far too obscure and complicated for us to 

 disentangle. Or — 



(2) They may originate independently in each individual organism 

 in reponse to some special and varying stimulus in the environment, 

 such as foodplant, temperature during critical periods in ontogeny, 

 etc., and in that case we should have to assume a much greater sus- 

 ceptibility to such stimuli in the male than in the female organism. 



It is evident that only by a course of careful experimental breeding 

 of C. sidphiueus, in all its varieties, could we hope to approach the 

 solution of these interesting problems. This of course remains one of 

 those tasks of the future that can be confidently recommended to 

 entomologists in quest of new lines of research, and if I have dwelt on 

 the subject at some length it has been not only for the sake of putting 

 on record as occurring in this country certain forms of insects, which 

 are recognised by definite varietal names on the Continent, but also to 

 hint, how in the manifestations of this far from rare beetle, there may 

 be biological problems of the deepest interest, which our most care- 

 fully applied varietal nomenclature helps in no way to solve. 



