No birds breed with such complete facility under confinement as the members of the great Duck family; yet, considering their aquatic and wandering habits, and the nature of their food, this could not have been anticipated. Even some time ago above two dozen species had bred in the Zoological Gardens; and M. Selys-Longchamps has recorded the production of hybrids from forty-four different members of the family; and to these Professor Newton has added a few more cases.[375] "There is not," says Mr. Dixon,[376] "in the wide world, a goose which is not in the strict sense of the word domesticable;" that is, capable of breeding under confinement; but this statement is probably too bold. The capacity to breed sometimes varies in individuals of the same species; thus Audubon[377] kept for more than eight years some wild geese (_Anser Canadensis_), but they would not mate; whilst other individuals of the same species produced young during the second year. I know of but one instance in the whole family of a species which absolutely refuses to breed in captivity, namely, the _Dendrocygna viduata_, although, according to Sir R. Schomburgk,[378] it is easily tamed, and is frequently kept by the Indians of Guiana. Lastly, with respect to Gulls, though many have been kept in the Zoological Gardens and in the old Surrey Gardens, no instance was known before the year 1848 of their coupling or breeding; but since that period the herring gull (_Larus argentatus_) has bred many times in the Zoological Gardens and at Knowsley. There is reason to believe that insects are affected by confinement like the higher animals. It is well known that the Sphingidae rarely breed when thus treated. An entomologist[379] in Paris kept twenty-five specimens of _Saturnia pyri_, but did not succeed in getting a single fertile egg. A number of females of _Orthosia munda_ and of _Mamestra suasa_ reared in confinement were unattractive to the males.[380] Mr. Newport kept nearly a hundred individuals of two species of Vanessa, but not one paired; this, however, might have been due to their habit of coupling on the wing.[381] Mr. Atkinson could never succeed in India in making the Tarroo silk-moth breed in confinement.[382] It appears that a number of moths, especially the Sphingidae, when hatched in the autumn out of their proper season, {158} are completely barren; but this latter case is still involved in some obscurity.[383]