Aldrich and Turley describe a certain insect which excites the sexual feeling of the female by manipulating a sort of bubble, or air-balloon, the glistening white appearance of which attracts the female, and which is probably produced by some modification of the anal organs. Giving an account of the sexual act, they say that, from a number of males gathered about her, the female, without hesitation, selected for her mate the one with the largest balloon, reversing the usual position by mounting upon his back. After the copulation had begun, the pair would settle down towards the ground, select a retired spot, and the female would alight by placing her front legs across a horizontal blade of grass, her head resting against it in such a way as to brace the body for the act. Here she would hold the male beneath her until it was completed; he meanwhile rolling the balloon about in a variety of positions—juggling with it, so to speak. After the male and female parted the balloon was always dropped by the former and greedily seized upon by ants.

In the love-making of animals the male plays the most active part, fighting for the female and surrendering her only when confronted by a stronger antagonist. Colors, odors and sounds, as do the colors and odors of plants, bear in some way a close connection with the reproductive function of most animals. Thus, frogs and toads have a sexual character in the musical notes of the male which is exceedingly interesting; and the musky odor emitted from the submaxillary glands of the crocodile, during the mating season, has been generally commented on by naturalists.1 At the same season the anal scent-glands of snakes are in full function, as are also the corresponding glands of the lizard. Many of the larger mammals are odoriferous during the rutting season, the female thus attracting the male, and the female genitalia of all animals have an odor both characteristic and, generally, disagreeable to man.

The musk-duck during pairing season emits a strong musky smell, although deficient in beauty of plumage, the female attracting the male, by the odor alone, from quite considerable distances; and sexual colors, and the power of song, as has been remarked by Mr. Wood, are, as a rule, complementary to each other among birds.* Thus, among most birds, the best songsters are plain colored; while the brilliantly tinted birds of the tropics are, as a rule, destitute of the power of song. The musk-deer, also, which is well known for its almost intolerable perfume, is an entirely silent animal;* and the wild camel of the Kum-tagh desert, "uttering no sound even in the rutting season, finds his consort by scent alone."* Nor must this fact be accepted as a refutation of my former statement as to the small part smell plays in the sexual processes. The dog's scent is not sexual, yet it guides him to his prey equally unerringly.

In his admirable work on "Darwinism" (p. 284), Mr. Wallace gives it as his opinion that the various sounds and odors of animals, which are peculiar to the male, serve either to indicate his presence or as a sexual call to the female, and that the production, intensification, and differentiation of these sounds, and odors, are clearly within the province of natural selection.

For further information on this remarkably interesting subject, the reader is referred to Darwin's "Animals and Plants under Domestication," n, 102,et seq,; Tillier, "L'lnstinet Sexuel;" the two remarkably complete volumes by Groos, and Professor Lloyd Morgan's "Animal Behavior."*