REPRODUCTION AND SEX 509 



between male and female is physiological, depending on some* 

 radical difference in metabolism. 



But another way of looking at the case has been suggested by 

 Goldschmidt. He regards the influence of the proboscis secretion as 

 stimulating precocious sexual differentiation, whereas Baltzer 

 thought more of the retardation of development. Moreover, Gold- 

 schmidt suggests that there are from the start male larvae and female 

 larvae. Those larvae that have the Mendelian factor for femaleness 

 will always develop into females. Those that have the Mendelian 

 factor for maleness will usually become males if they settle on 

 adults. But if the settling down lasts for a short time only, the 

 larvae will become inter-sexes. And if the parasitic stage is skipped 

 altogether, the larvae with the male determinant will develop through 

 transitory inter-sexuality into female forms. It may be, then, that 

 some revision of Baltzer's interpretation will be required in the light 

 of Goldschmidt's suggestions. 



COURTSHIP AMONG ANIMALS 



What may without any very appreciable metaphor be called 

 animal courtship is as diverse in its expressions as there is mani- 

 foldness in individuality. We must not think of the courting 

 creature as thinking out a programme, or meditating on its music, 

 or planning an attractive and ceremonial approach, as might be 

 true of human kind. It is rather that the animal is fuU of passion 

 and desire, and lets itself go, in an abandonment of self-expression, 

 along lines which are prescribed by its inborn instinctive equipment : 

 and these lines, whether of song or dance, of display or tournament, 

 it may be of luminescence or fragrance, have been sifted out — in 

 the course of millennia — as those that proved most effective in 

 awakening interest and admiration, sex-excitement, and the 

 sympathetic resonance of passion in the desired mate. No doubt 

 there are individual variations, as in the song of the nightingale and 

 the lark, but the main lines are prescribed by the hereditary endow- 

 ment. Little improvements are always being added, especially when 

 the males are in the majority; which, unless polyandry supervenes, 

 is generally a good thing for the race, since it leads to a higher 

 valuation of the females. In the vast majority of cases, it is, of course, 

 the male who does most of the wooing ; but there are quaint excep- 

 tions that give us pause. Such are the Grey Phalaropes, which 

 breed in the Far North and pass our shores or linger on them in 

 autumn. For in this attractive bird, the female does the courting, 

 and the male the brooding. 



Naturalists, like other fallible men, are often apt to take over- 

 simple views of familiar occurrences; and some are quite satisfied 



