OF WASHINGTON. 233 



Koch's families are three; the Argasidae with the genera Argas, 



Ornithodorus, 



Ixodidae " " " Hyalomma, 

 Haemalastor, 

 Amblyomma, 

 Ixodes, 



Rhipistomidae " " Dermacentor, 



Haemaphysalis, 



Rhipistoma, 



Rhipicephalus. 



This classification is based upon such perfectly natural 

 principles that in studying the American Ticks, of which I 

 have been able to examine a great number, besides many exotic 

 forms, I can do no better than to follow this great Arachnolo- 

 gist with some modifications and additions. 



In regard to the systematic value of this group of Arachnida 

 I will consider it as a suborder of the Acari, and, as Degeer, 

 long before Koch, gave the name Ricinus to a genus of Pedi- 

 culi, I propose for this suborder the name Cynorh&stea, the 

 oldest name for Ticks, since Homer said : ' ' Knda kuon keit 

 Argos enipleios Cynorhaesteon there laid Argos, the dog, 

 covered with Ticks. ' ' 



Aristotle and the old Greeks called the Ticks ( ' Croton ' ' on 

 account of their resemblance to seeds of the Castor tree which 

 bore the name Croton in ancient Greece. The Romans called 

 our animal ' ' Ricinus ' ' for the same reason, for in their language 

 the name of this tree was Ricinus, a name which is still used in 

 the scientific botanical nomenclature. (Ricinus communis 

 Ivinne.) 



If we admit the family Argasidae into the Cynorhsestea 

 and hold with Koch that its natural position is here, rather 

 than in the Gamasidae, on account of the great homology of the 

 mouth parts and other points of undoubtedly close relationship, 

 we have to divide the suborder into two groups the CATASTO- 

 MATA and the ANTISTOMATA. 



Suborder CYNORH^STEA. 



1. Capitulum inserted below the superior or dorsal surface, palpi not 



excavate at their inner side I. group Catastomata 



2. Capitulum inserted on a level with the dorsal surface, palpi longitudi 



nally excavate at the inner side, enclosing the sides of the 

 rostrum II. group Antistomata 



Into the Catastomata I place, in addition to the family 

 Argasidae, with the genera Argas Latr. and Ornithodorus 

 Koch, the family Kschatocephalidae, based upon the genus 

 Bschatocephalus Frauenfeld, which seems to form a connecting 

 link between the two tribes. This, however, is provisional. 



