274 ENTOMOLOGICAL SOCIETY 



the lateral sides of the abdomen, leaving it free only at its pos 

 terior region. 



Third, The posterior border of the abdomen is divided by 

 eleven lines into thirteen small lobes, probably the remains of an 

 articulation in the primitive type ; which theory is strengthened 

 by the fact that we find several transversely curved lines running 

 over the posterior abdominal region, one generally from the sec 

 ond lobular division line of the posterior margin, around the anus 

 and to the corresponding place on the other side ; another, prob 

 ably a double one, from the anus backward to the impar (mid 

 dle) lobe. 



Although the cephalothorax is blended with the abdomen into 

 one solid body, the mouth parts are free and form a little head- 

 like structure in front of the body. This part, which was con 

 sidered the head by the older writers, and even by some of the 

 present day, as Kolenati and Packard, and which I will call 

 capitulum, in conformity with Haller's nomenclature of the same 

 part in the Gamasidae and other allied families, is inserted into 

 the front of the body in different ways, which give cause for the 

 division of this sub-order into three divisions. The first differ 

 entiation is the place in which the capitulum is inserted into the 

 body ; for while in some genera the capitulum is invisible from 

 the dorsal view because it is inserted below the projecting upper 

 surface, in others it is inserted on the same level with the dorsal 

 surface. The first section I call Catastomata, and the second 

 Antistomata. But in the Antistomata we notice two different ways 

 of insertion ; in one, the front margin of the body, the clypeus, is 

 excavated, and in this concave region the capitulum is situated 

 this is the great group of the Ticks proper ; in a small number 

 of genera the clypeus is not excavate and the capitulum stands 

 squarely against it. 



In treating, in this paper, only of Ticks, I would be understood 

 to mean only those Cynorhasstea in which the capitulum is sunk 

 in the excavation of the clypeus the Antistomata. 



The capitulum or pseudo-head of all Cynorhaestea consists of 

 three principal parts : the basal piece, the rostrum, and the 

 palpi. 



The basal piece or capitulum proper is a broad, thick, sub- 

 triangular, ring-like organ, with a somewhat flattened upper and 



