In justice to Darwin it should be remarked that he himself fully realized, and carefully points out, the inconceivability of the application of the Sexual Selection theory to the Mollusca. In commenting on the beauty of colour and shape which many species display, he remarks: “The colours do not appear in most cases, to be of any use as a protection; they are probably the direct result, as in the lowest classes, of _the nature of the tissues_[1]: the patterns and the sculpture of the shell depending on the manner of growth.” Just so: and this is surely the fundamental explanation of ornament, using this term in its widest sense, everywhere in the Animal Kingdom. The peculiarities and eccentricities of behaviour, which occur among the higher groups, act as “aphrodisiacs” to hasten reproduction because this confers an advantage, the earliest to produce offspring—so soon as the conditions for their nurture are favourable—having the best chance of survival. Premature sexual activity is checked by the death of the offspring. [1] Italics mine. It has been contended that the hermaphrodite condition represents the primitive mode of reproduction among the multicellular animals—that is to say, all animals above the level of those whose bodies are composed of but a single cell, or particle, of protoplasm—but this view is probably erroneous, and the hermaphrodite state must be regarded as a secondary condition, a later innovation. More remarkable are the facts concerned with that singular form of reproduction known as parthenogenesis, or the production of offspring by virgin females. This is undoubtedly a degenerate sexual condition occurring as a normal mode of reproduction, among the microscopic “Rotifers,” _e.g._ the “Wheel-animalcule,” Crustacea, and Insects, and in varying degrees of intensity. The most familiar instances of Parthenogenesis are furnished by the Hymenoptera, and notably by the Bees and the Aphides. There are certain cases among the Rotifers where no males have ever been found, and it is possible that they have become entirely suppressed, but in every other case the periodical advent of males is an absolute essential for the continuation of the race. Perhaps the least degenerate of these types are the Bees, wherein we meet with well-developed, highly-organized males and females, which, in their sexual relationships, are perfectly normal. But in the fulfilment of the mating instincts in these insects, a most amazing sequence of events is revealed such as are without parallel in the rest of the Animal Kingdom. The story has been charmingly told already by Maeterlinck, in his delightful “Life of the Bee,” and it has been told again by Tickner Edwardes, with less of poetry, perhaps, but still fascinatingly: and it must be told again now, but in a condensed fashion.