The description of the species is made from specimens mounted on slides, which were given to me by the late Dr J. Waterston for examination. As all the specimens were flattened and very much distorted by the pressure of the coverslips, it was impossible to determine whether they belonged to one of the known species. Permission having been received for their remounting, the following method was adopted. The slide was placed in xylol and, after the Canada balsam had dissolved, the specimen was transferred to fresh xylol and then to absolute alcohol. In this medium the wings were detached and, after being cleared in oil of cloves, mounted on a slide. The wingless body was passed through spirits of diminishing strengths to water, and then to caustic potash, and boiled. During boiling the specimens become soft and acquire their natural form. If any parts of the body are still distorted after the boiling they may be restored to their natural position with two dissecting needles. This method of remounting gave a very satisfactory result, although the specimens had been mounted more than 10 years. The further manipulation, together with the morphology of the genus, have been described elsewhere (Jobling, 1930).