The systematic study of the Hydrachnidæ, or water-mites, of Scotland appears to have been entirely neglected until within the last few years, and, so far as I am aware, the only communications dealing with Hydrachnids found in Scotland are two noted in the list of literature cited.

Of the life-history of Hydrachnids we have only a limited knowledge, and that may in time be modified as further information is acquired. At present the life-cycle appears to be in four definite stages—the egg, the larva, the nymph, and the imago. When an egg is hatched, a six-legged larva emerges, and apparently its main function is to find a suitable host to which it may attach itself.