The examination of a large number of individual lice in India, where the facilities for obtaining material are unusually good, has impressed me with the fact that the characters ordinarily given as differentiating corporis from capitis are all to a greater or less extent inconstant and unreliable. In general, however, capitis is more heavily chitinized and the chitin is of a darker colour with less smooth outlines. The size is very variable, but corporis has an easier life and is more often large.