There are however couples among insects. Among coleoptera there are the "purse-maker," the necrophore. Stercorian geotrupes, lunar copris, onitis bison, sisyphus, work soberly side by side preparing the larder for their coming families. In these cases, the male seems master, he directs the manœuvres in the complicated operations of the necrophores. A couple get busy about a corpse, say of a field mouse; nearly always one or two isolated males join them, the troop is organized, one sees the chief engineer explore the territory and give orders. The female awaits them, motionless, ready to obey, to follow the movement. As soon as there is a couple the male necrophore commands. The male assists the female during the work of arranging the cell and the laying. Most purse-makers, sisyphus or copris make and transport together the pill which serves as food for the larvæ; their couple is just like that of birds. One might believe that in this case monogamy is necessitated by the nature of the work; not at all: the male in other quite closely related species, sacred scarab, for example, leaves the female alone to build the excremental ball in which she encloses her eggs.
Coming up to vertebrata one finds also certain examples of a sort of monogamy: when the male fish serves as hatcher for his own eggs, either carrying them in a special pouch, or heroicly sheltering them in his mouth. This is rare, since, usually, the two sexes of fish do not approach each other, do not even know each other. Batrachians, on the contrary, are monogamous; the female does not lay save under male pressure, and it is so slow an operation, preceded by such long manœuvres that the whole season is filled with it. The male of the common land toad rolls the long chaplet of eggs about his feet as soon as it is divided, and goes in the evening to place it in the neighbouring pool. Nearly all saurians seem also to be monogamous. The he and she lizard form a couple said to last several years. Their amours are ardent, they clasp each other closely belly to belly.
Birds are generally considered monogamous, save gallinaceæ and web-footed birds; but exceptions appear so numerous that one would have to name the species one by one. The fidelity of pigeons is legendary, and is perhaps only a legend. The male pigeon certainly has tendencies to infidelity and even to polygamy. He deceives his companion; he goes so far as to inflict upon her the shame of having a concubine under the conjugal roof! And these two spouses, he tyrannizes over them, he enslaves them by beating. The female, it is true, is not always of an easy disposition. She has her caprices. Sometimes, refusing her mate, she deserts him and gives herself to the first comer. One will not find here any of the zoölogical anecdotes on the industry of birds, their union in devotion to the specie. The habits of these new-comers in the world, are very unstable; yet among certain gallinaceæ, monogamous for exception, like the partridge, the males seem pulled by contrary desires, they undergo the couple rather than choose it, and their share in the rearing of young is often very slight. One has seen the male red partridge, after mating, abandon his female and rejoin a troop of male vagabonds. The nightingales, perfect pair, sit on the eggs turn by turn. The male, when the female comes to relieve him, remains near by and sings until she is comfortably settled on the eggs. Still more devoted is the male talegalle, a sort of Australian turkey. He makes the nest, an enormous heap of dead leaves; when the female has laid, he watches the eggs, comes from time to time to uncover them for exposure to the sun. He takes his share of watching the young, sheltering them under leaves until they are able to fly.