The actual mating of Spiders, the act of coition, is peculiar, and demands notice, for the orgasm is not accomplished at the moment of the ejection of the sexual products. The male discharges the seminal fluid upon a small web woven for the purpose, and the liberated spermatozoa are then sucked up into a tube—the _receptaculum seminis_—which lies coiled up within a hollow bulb attached to the base of the last joint of the leg-like feeler, or “pedipalp” at the base of the head. The precious fluid is there stored and retained until the moment arrives when these palps can be thrust into die genital aperture of the female, and their contents discharged for the second and last time. This is the critical moment of the Spider’s life, and it is noteworthy that it should occur now, instead of at the moment of the discharge from the body. The ejection from the palpal organ is effected by means of a fibro-elastic bag, in its normal, collapsed, state spirally disposed round the base of the bulb which contains the sperm tube. Immediately preceding copulation this elastic bag or “hæmatodocha” becomes turgid with blood, and it is probably the pressure thus exerted on its base which affords the final fury of desire without which, indeed, one might well imagine the necessary courage for copulation would never be raised, at any rate, in the case of some species. Strange as these facts are, the nice adjustment of the instincts for their effectual performance is, by comparison, stranger still. By what subtle sense is the male Spider informed of the importance of the fertilizing fluid which escapes his body? What prompts him before its escape to prepare a web for its reception? What prompts him after its deposition to collect it within the palp till it shall be needed? The least defect in the instincts appertaining to these vitally important acts would mean the extinction of the race. We cannot suppose that the nature of their performance is in any way realized by the performer, and this makes their orderly execution the more wonderful. [Illustration: Plate 34. MALE ASTIA DISPLAYING BEFORE THE LESS BRILLIANT FEMALE.] [Illustration: From drawings, T. Carreras, in “Marvels of the Universe.” MALE ICIUS DISPLAYING. The “courtship” of the male spider takes the form of a “display” recalling that of birds. He commonly ends in being eaten by his mate. Face page 242.]