Classification 109 



for it brings Ixodes, Aponomma and Haemaphy salts together on the 

 one hand, and Amblyomma, Hyalomma, Rhipicephalus and Dermacentor 

 on the other. Neumann considers it essential to take as a basis of 

 classification some external feature which is determined by a difference 

 in anatomical structure. Such a feature is to be found in the grooves 

 on the ventral surface. This would lead us back to the principle 

 adopted by Canestrini (vide supra), who was struck by the affinities 

 existing between Hyalomma and Rhipicephalus. Canestrini did not 

 include Amblyomma and Aponomma under his Anopli, because he 

 confined himself to genera occurring in Italy. Neumann agrees that 

 Canestrini's groups Poliopli and Tetraopli are homogeneous, but that 

 this does not hold for the group Anopli, which includes Amblyomma 

 (Aponomma 1 ), Dermacentor and Haemaphysalis. (Amblyomma and 

 Aponomma are obviously allied, but Dermacentor and Haemaphysalis 

 remain disconnected.) Neumann attempted to represent the supposed 

 affinities between the different genera by the following plan, wherein 

 the position and length of the connecting lines indicate approximately 

 the degrees of affinity : 



Ixodes Haemaphysalis 



Hyalomma Amblyomma Aponomma 



Rhipicephalus Dermacentor 



Neumann adopts Canestrini's groups as sections in the subfamily 

 Ixodinae, substituting names derived from type genera for the cor- 

 responding names given by Canestrini, thus: 



Section I. Ixodeae (for Poliopli). 



„ 2. Rhipicephaleae (for Tetraopli). 

 „ 3. Amblyommeae (for Anopli). 

 Neumann characterizes the sections as follows : 



1. Ixodeae : ^ venter entirely covered by shields. Anal groove 

 contouring the anus in front and independent of the genital grooves. 

 Eyes absent. Capitulum elongate. 



2. Rhipicephaleae : £ venter bearing two adanal shields, usually 

 accompanied by accessory shields. Anal groove contouring the anus 

 behind and usually joining the genital grooves in front. Eyes present. 

 Capitulum long or short. 



3. Amblyommeae : j" venter devoid of shields. Anal groove as 

 under 2. Eyes often present. Capitulum as under 2. 



1 We regard Aponomma as simply a subgenus of Amblyomma. 



