_Plumages._--The downy young white rumped is much like the downy young of other tundra nesting species of sandpipers. From the stilt sandpiper it can be distinguished by its much shorter legs and shorter and slenderer bill, from the Baird by its more buffy face and breast, these parts being pure white in _bairdi_, and from the least by paler and duller browns in the upper parts and by white, instead of buffy terminal tuft spots. The crown, back, rump, wings, and thighs are variegated or marbled with "Sanford's brown," or "tawny," and black, dotted, except on the front half of the crown, which is mainly bright brown, with whitish terminal tufts. The forehead, a broad superciliary stripe, the sides of the head, throat, and breast are pale buff or buffy white; the remaining under parts are grayish white. A median frontal stripe of black terminates in "tawny" toward the bill; there are extensive black areas on either side of the crown and on the occiput. The nape is grizzly, buff, gray and dusky. In juvenal plumage the crown is sepia with "tawny" edgings; the back, rump, tertials, and scapulars are sepia, with "tawny" edges, and some of the feathers of the mantle and scapulars are also white tipped; the under parts are white, but the breast is suffused with light buff and narrowly streaked with dusky; the median and lesser wing coverts are broadly edged with light buff or whitish. The postjuvenal molt of the body plumage usually occurs in September and October, mainly in the latter month, but sometimes not until November. The upper body plumage is not all molted, so that first winter birds can be distinguished by tawny or buffy edged feathers in the mantle and by the juvenal wing coverts. The next partial prenuptial molt apparently removes all traces of immaturity. Adults have a prenuptial molt, beginning in March, of the under-body plumage, most of the upper-body plumage, sometimes the tail, and some of the wing coverts. But this is almost immediately preceded by the delayed molt of the remiges in January and February, so that it seems to be a nearly complete prenuptial molt, which is barely finished before the birds start on their long northward migration. The postnuptial molt of adults, beginning in August and often lasting into October, involves only the body plumage, the tail, and some scapulars, tertials, and wing coverts. The gray winter plumage, so different from the brightly colored spring plumage, is seldom seen in its completeness before the birds go south. _Food._--Very little seems to have been published on the food of the white-rumped sandpiper, but W. L. McAtee (1911) gives it credit for eating some injurious insects and worms, such as grasshoppers, the clover-root curculio, which is injurious to clover, and marine worms (_Nereis_), which prey on oysters. Stuart T. Danforth (1925) says that four collected in Porto Rico--