234 ENTOMOLOGICAL SOCIETY 



Group I CATASTOMATA. 



1. Palpi considerably longer than rostrum, cylindrical, ist palpal joint 



longest, 4th as long as 3d ; not retractile family Argasidae 



2. Palpi not longer than rostrum, subglobose, ist palpal joint shortest, 



ring-like, 4th joint shorter than 3d ; retractile 



family Eschatocephalidae. 

 genus Eschatocephalus Frfld 



Family ARGASID^. 



1. Capitulum hidden under a projecting, beak-like prominence, so close 



to the anterior margin that the tips of the palpi project from 



under the body and are visible from above 



genus Ornithodorus C. K_ 



2. Capitulum at least by its length removed from the anterior margin, 



body without a projecting beak-like prominence in front 



genus Argas Latr 



Koch based the criterion of these two genera upon the pres 

 ence of eyes in Ornithodorus and their absence in Argas. A 

 close examination, however, of these two genera, which are 

 indigenous in the United States and not uncommon in the 

 Southern and Western States, convinced me that the presence 

 of eyes in Ornithodorus is based upon an erroneous observation, 

 and another differentation is therefore substituted. 



Argas is so far recorded from Texas, by Prof. Packard, who 

 described it in " Report Geol. Survey, 1873, p. 740," &=> Argas 

 americanus. 



I have received, however, a lot from L,akeside, California, 

 where they were found in a chicken-house. 



The genus Ornithodorus is also found in the Southern and 

 Western States and abundantly also in Central and South 

 America, where it is a great pest to cattle and llamas (Brazil and 

 Chile) and it has been found so far in the United States in 

 Iowa, California and Arizona. 



The genus Eschatocephalus Frauenfeld has been found, so 

 far, only in caves in Austria. Although the capitulum is 

 inserted below the dorsal surface, the palpi more nearly resem 

 bles those of the Antistomata ; the family Eschatocephalidae is 

 therefore provisionally placed in the group of Catostomata. 

 Group II. ANTISTOMATA. 



This group comprises those species which are commonly 

 known by the name of Ticks, and I divide them into three 

 families : 



f Front of the body, opposite the insertion of capitulum straight 



j I family Haemalastoridse. 

 ' L Front of body, excavate 2; 



