_Pediculus corporis_ (= _P. vestimenti_) the body louse, is larger than the preceding species, the female measuring 3.3 mm., and the male 3 mm. in length. The color is a dirty white, or grayish. _P. corporis_ has been regarded by some authorities as merely a variety of _P. humanus_ but Piaget maintains there are good characters separating the two species. The body louse lives in the folds and seams of the clothing of its host, passing to the skin only when it wishes to feed. Brumpt states that he has found enormous numbers of them in the collars of glass-ware or grains worn by certain naked tribes in Africa. Exact data regarding the life-history of this species have been supplied, in part, by the work of Warburton (1910), cited by Nuttall. He found that _Pediculus corporis_ lives longer than _P. humanus_ under adverse conditions. This is doubtless due to its living habitually on the clothing, whereas _humanus_ lives upon the head, where it has more frequent opportunities of feeding. He reared a single female upon his own person, keeping the louse enclosed in a cotton-plugged tube with a particle of cloth to which it could cling. The tube was kept next to his body, thus simulating the natural conditions of warmth and moisture under which the lice thrive. The specimen was fed twice daily, while it clung to the cloth upon which it rested. Under these conditions she lived for one month. Copulation commenced five days after the female had hatched and was repeated a number of times, sexual union lasting for hours. The female laid one hundred and twenty-four eggs within twenty-five days. The eggs hatched after eight days, under favorable conditions, such as those under which the female was kept. They did not hatch in the cold. Eggs kept near the person during the day and hung in clothing by the bedside at night, during the winter, in a cold room, did not hatch until the thirty-fifth day. When the nymphs emerge from the eggs, they feed at once, if given a chance to do so. They are prone to scatter about the person and abandon the fragment of cloth to which the adult clings. The adult stage is reached on the eleventh day, after three molts, about four days apart. Adults enter into copulation about the fifth day and as the eggs require eight days for development, the total cycle, under favorable conditions, is about twenty-four days. Warburton's data differ considerably from those commonly quoted and serve to emphasize the necessity for detailed studies of some of the commonest of parasitic insects.