CLASSIFICATION. 13 



torida3, Ixodidse, and lvlnpistomida\ The Hsenialastoridio of Marx 

 is based on a misconception; the type of Ila'inalaxto)' is a IIij(dornina. 

 while Sarconyssus belongs to Eschatocepliahix. 



These classifications have placed a great deal of prominence on the 

 length of the 2:>alpi. Lahille, in 1005, in his tabnlar arrangement of 

 the genera, has subordinated this character to others, and I fully agree 

 with him. He places, and I believe correctly, Atnhlyomma near Der- 

 macentor instead of near Ixodes. Lahille, however, bases his main 

 divisions of the Ixodidse on certain characters of the male; whether 

 the male has five anal plates (Perissopli), or four anal plates (Arti- 

 opli), or no anal plates (Anopli). By this arrangement he sepa- 

 rates Ilyalomma from Amblyomma, while other authors — and here 

 I agree with these latter — place these genera close together. In- 

 deed, the character used to distinguish the females of these two genera 

 is not always easy of verification, so that several writers have made 

 mistakes in this matter. 



Moreover, I fail to see the importance in secondary sexual charac- 

 ters that Lahille places upon them. They certainly are not of suf- 

 ficient value to characterize groups higher than genera, and are better 

 employed for groups of les-ser rank. 



Therefore I have made use of another character to divide the 

 Ixodidffi into two groups, namely, the presence or absence of a curved 

 groove in front of the anus and continued back each side. In 

 Ixodes this groove is present, in other ticks it is absent, and in most 

 forms there is a small groove behind the anus, not seen in Ixodes. 

 Ixodes differs in various other ways from the other ticks, notably in 

 lacking festoons to the posterior margin of the body. I have there- 

 fore placed Ixodes (and Cerat'ixodes) in a subfamily, Ixodinse, as 

 opposed to the other ticks, Amblyommina\ Rhipiccphcdus (and 

 Mai'garojnis)^ by the peculiar shape of the capitulum, have long 

 been considered distinct from other ticks, and for them a tribe is es- 

 tablished, the Ehipicephalini ; likewise Ilamajjhysalis., by its peculiar 

 palpi, will warrant another tribe, the Ha?maphysalini. Amblyom/na, 

 Hyalomma, and Aponomma are more closely related to each other 

 than to Dermacentor. Two more tribes will thus be requisite, the 

 Dermacentorini and the Amblyommini, distinguished not only by 

 the length of the palpi, Init also by the lengths of the divisions of the 

 tarsi. These characters will apply to both sexes and even to the 

 nymphal forms. Other less important points aid in distinguishing 

 the groups, as evidenced by the synoptic tables. 



Long after the above was written, I received a paper by Mr. 

 Cecil Warburton (Notes on Ticks, December, 1907), in which he 

 proposes practically the same classification as I have proposed above. 

 He uses the position of the anal groove to separate Ixodes from all 

 other Ixodida?, but for this group and all his groups uses new names, 



