Among lower animals there are curious cases of the greater strength and size of the female. Thus, among spiders, the female is nearly twice as bulky as the male. She makes, in many cases, a nest ready for her young, and is visited there by the wandering irresponsible male, who, in spite of great danger to himself, is irresistibly attracted to seek a brief caress from the terrible spideress. She is terrible, not only on account of her bulk, but because she makes a rule of killing, and sucking the blood of, her infatuated admirer unless he is sufficiently alert and agile to escape from her side more quickly than he came to it. The courtship of spiders is a very interesting bit of natural history. The males execute a sort of dance, and are strangely excited by the vibrating note of a tuning fork. Two American naturalists, Mr. and Mrs. Peckham, and also Dr. McCook, have studied this subject in great detail. A strange-looking, dark green worm, as big as a walnut, with a ribbon-like trunk six or eight inches in length attached to its mouth, lives in holes in the rocks in the Mediterranean. A similar worm has been found off the Norwegian coast. Fanciful names are given by zoologists to these two worms--the first is called Bonellia, the second Hamingia. It does no harm to cite their names, and I do so with an apology to those who do not like names. These goodly sized worms are females, only females. For years the corresponding male was unknown. At last a minute creature one-eighth of an inch in length, like a tiny fragment of green thread, was found crawling about on and into these big green Bonellias. Its structure when it was examined with the microscope proved it to be the adult male of the worm on which it was crawling. It was so insignificant and minute as to escape all observation except that of a trained naturalist searching for it with a magnifying glass. Some seven or eight of these diminutive males are found on one female, infesting her as fleas infest a mouse, and of about the same relative size. The microscopic husband of the Norwegian Hamingia it was my good fortune to discover many years ago, when I was dredging marine animals in the deep waters of the Stavanger Fjord.