RELATING TO SECONDARY SEXUAL CHARACTERS. 59 



"The spider has four pairs of legs, and all are equally available for display 

 or locomotion, and since all the movements are slow and on the ground they 

 are entirely open to observation and study, and we arc thus in a portion to 

 decide by facts whether their activity is simply an outlet for superfluous 

 energy, and therefore meaningless, or whether there is a purpose in it. If the 

 purpose of the antics is only to let off energy, then wo should expect one- pail 

 to be flourished around quite as often as another, and that the pair flourished 

 should as frequently be one that was not ornamented as one that was; and, 

 moreover, their movements ought not to be of such a nature as to display the 

 color or ornament more frequently than the law of chance would explain. If 

 the spider almost always moves the ornamented legs, and in such a way, too, 

 as to bring out their beauty, it would seem to us, to say the least, highly 

 improbable that the dance of the spider was merely a meaningless overflow of 

 surplus energy. Such an explanation leaves much that needs explanation. 

 The facts are, that the best foot is put forward; and this is just what Darwin's 

 theory requires and explains. Under Mr. Wallace's view the facts are inex- 

 plicable. The better to show that these movements are not simply meaning- 

 less outlets of high vigor, we illustrate the several positions by figures taken 

 from nature (figs. 7-12). The figures would seem to prove that the legs that 

 are ornamented or contrasted in color are also the legs that are usually flour- 

 ished; that where none of the legs have special ornament, then all are used; or, 

 as sometimes happens, when an unornamented leg is used the movements are 

 of such a character as to display some ornament that would otherwise have 

 been more or less hidden from the female." (Peckham, loc. cit., p. 147.) 



In the tarantula, Petrunkewitsch finds that sight plays no role in 

 mating — that it is due entirely to accidental contact between the male 

 and female. Here the sexes are closely alike, except for a pair of hooks 

 on the front legs of the male, by means of which he grasps the mandibles 

 of the female, holding them during the elaborate process of trans- 

 ference to her genital opening the sperm that he has already collected 

 in the genital spoon on his palpi. The hooks serve to guard the 

 male against injury or death, w r hile at the same time they aid him in 

 the act of coitus. 



In a common spider, Mceiia villata, two kinds of males exist. Both 

 have been seen to mate with the same female. No preference is given 

 to either type. The difference between them, according to Painter, 

 is connected with or caused by an additional pair of chromosomes in 

 the gray male. The two types may therefore have no connection with 

 sexual selection, but be directly due to a difference in the chromosome 

 group. 



Montgomery, who made observations on the courting habits of 

 several species of spiders, states that his ''general theoretical con- 

 clusions were quite different from those of the Peckhams." It turns 

 out, however, that his objection to their view is based entirely on their 

 assumption that the male is conscious of his display and that the 

 female is guided by an esthetic sense in selecting the more beautiful 

 male. It should be pointed out that even after the removal of tl 



