Published online by Cambridge University Press: 06 April 2009
The systematic position of the blood-sucking Gamasides Leach, 1815, is still very unsatisfactory. In his work on external parasites, Ewing (1929) recognizes the two families Parasitidae and Dermanyssidae, distinguishing them chiefly by the form of the chelicerae. The former family to which Laelaps and related genera belong is defined by Ewing as follows: ‘chelicerae of a generalized type having the tips incurved and being provided with teeth, and the fixed arm usually bearing a seta near its tip’. The Dermanyssidae have modified chelicerae, ‘usually without teeth and fixed arm always without setae’. In this family Ewing puts the genera Liponyssus, Dermanyssus and related ones.