112 Classification 



into three families : Argasidae, Ixodidae (with long palps) and Rhipi- 

 stomidae (with short palps). The relative length of these structures 

 is certainly convenient in the practical work of determination. Banks 

 (1908, p. 12) objects to too much weight being laid on the relative 

 length of the palps, partly on the ground that it hardly permits us to 

 " distinguish some species of Amblyomma from Dermacentor." Donitz 

 does not approve of Neumann's subsequent adoption (1904) of the 

 plan of Canestrini (1890), the latter's Poliopli, Tetraopli and 

 Anopli corresponding to Ixodeae, Rhipicephaleae and Amblyommeae 

 of Neumatm. As Donitz points out, Amblyomma are not Anopli; a 

 number possess small chitinous plates 1 (analogous to the plates in 

 Ixodes) situated posteriorly upon the ventral surface. Again, Mar- 

 garopus has a ventral plate corresponding to the median plate in 

 Ixodes, but Margaropus, by its general structure, is allied to Boophilus 

 and Rhipicephalus, i.e. Tetraopli (Rhipicephaleae), and not to Poliopli 

 (Ixodeae). Banks (1908, p. 13) very properly criticizes the classification 

 of Lahille (190-5), which is based on the characteristics of the </\ and 

 thus separates Hyalomma widely from Amblyomma, most authors 

 agreeing that they are allied, the ?s being at times difficult to 

 distinguish. Banks fails to see "the importance of secondary sexual 

 characters" which lead to Lahille's classification, and considers that 

 they " are certainly not of sufficient value to characterize groups higher 

 than genera and are better employed for groups of lesser rank." Donitz 

 (1910, p. 401) likewise objects to Lahille's classification on the ground 

 already stated that Amblyomma are not Anopli, aud that Margaropus 

 would be classed as Perissopli, whereas they are closely related to 

 Artiopli. He agrees with Warburton and with Banks in separating 

 the genus Ixodes widely from the other genera, because of the structure 

 of the anal groove, apart from other important differences. Donitz 

 (p. 403) divides the Ixodidae into three divisions : I. Ixodeae (one 

 genus, Ixodes), II. Amblyommeae (=Longirostrata of Warburton, with 

 three genera : Amblyomma, Aponomma, Hyalomma), and III. Rhipice- 

 phaleae (=Brevirostrata of Warburton, with six genera: Rhipicephalus, 

 Boophilus, Margaropus, Dermacentor, Rhipicentor and Haemaphysalis). 

 Banks (1908, pp. 13, 14) does not agree with the classification of 

 Warburton in so far as the latter places Dermacentor with Rhipicephalus. 

 Banks considers this ill-advised, and places Dermacentor close to Am- 

 blyomma. The genus Rhipicentor Nuttall and Warburton, 1907, however, 

 directly links Rhipicephalus to Dermacentor, as is indicated by the 

 1 " Plaques " in our descriptions, see Fig. 135 a. 



