On the Sarcoptes of Man1
With 9 Text-figures.) OUR knowledge of the systematics of the genus Sarcoptes is in an unsatisfactory state. About a score of species have been admitted, many of which have nevei been seen since they were described. Many of the descriptions date from between sixty and seventy years ago, a period when microscopes and microscopical technique were barely adequate to cope with so difficult a genus as Sarcoptes is. In order to provide a basis for further study of Sarcoptes, Warburton (1920)
... a critical survey of our knowledge regarding these mites. His review of the literature has proved invaluable to myself, and is the foundation on which I have worked. In the foregoing paper (pp. 114-145) I published an only too lengthy description of the Sarcoptes of the horse, finding that a full description of one form was necessary as a basis for comparison. Since we do not know what anatomical points are of systematic importance, attention was given to all details of the external anatomy. I propose to deal now with the Sarcoptes of man. It is commonly held that the "itch" is caused by a species or variety peculiar to the human race (Sarcoptes scabiei var. hominis (Hering)) and that this mite is separable on anatomical grounds from the sarcopts of other animals; it is believed that man is also attacked by "S. scabiei-crustosae" Fiirst., and that this mite, which produces symptoms graver than those of itch, is a "good species," separable from S. scabiei and from the species attacking quadrupeds by definite anatomical characters. This second sarcopt is however very little known, and the "Norwegian Itch" or "Crusted Scabies," of which it is the cause, is a rare disease.