Hydrachna williamsoni Soar, 1908

Species incerta

Material examined: Female, NHML, C.F.G. "Dr. C. F. George coll. 1925 VI 24 144". "Lincolnshire Dr.C.F.George Coll. 1925 VI 24. 144. Balsam, 1904". Location of holotype unclear.

Discussion: The only specimen known in European collections is obviously a juvenile. From many points of view it is similar to H. processifera (frontal area with poorly developed, roundish sclerite dots near postocularia, general shape of genital field, with L/ W 400/700, Cx­4 with a hook­like extension directed laterally). The transverse position of the gnathosoma and its appendages does not allow for measurements. As proposed by Gledhill & K.O. Viets (1976), this species should be considered a species incerta and not listed in faunistic inventories.