A^ntxals of the Teansvaal Museum. 



Tile rosti'uui comprises (1) two mandibles, each formed of a shaft, 

 the low ci- half of which is swollen to receive the insertion of muscles, 

 while tile upper half is fiattened and narrow^ terminated in front by a 

 finger or digit, recurved in a hook at its tip. The base of the digit is 

 wide and swollen ; on its dorsal surface it bears two unequal apophyses, 

 each with one or more processes and teeth, recurved, one of which is 

 always terminal. These mandibles are wrapped throughout their full 

 extent in a membranous sheath, a prolongation of which extends over the 

 digit ; (3) a hijpostome shaped like a dart, armed on its lower face with 

 backward 2Ji'ojecting teeth placed symmetrically on each, half ; (3) two 

 palpi composed of four articles each. 



Respiration is by tracheal tubes opening to the exterior through two 

 stigmata, surrounded by stigmatic plates, circular or lunate in outline, 

 and situated near the fourth pair of coxae. 



Legs with six articles (seven or eight by the apparent division of one 

 or two articles into two parts) ; coxae immovable ; tarsi ^^rovided with two 

 claws, with or without a sucker-like disk called the amlidacre. The tarsus 

 of the first pair bears on its dorsal edge, near the distal extremity, a cup- 

 like depression, tlie organ of hearing known as " Haller's organ.'' 



Larvae with six legs, without sexual orifice, and without large 

 stigmatic plates ; respiration takes place through one to four pairs of small 

 openings along the lateral edges. 



Xymplis with eight legs, and no sexual orifices ; two large stigmatic 

 jDlates present. 



The members of the family live as parasites on mammals, birds, and 

 land reptiles, the blood of which they suck l)y fixing their rostrum into 

 the skin. The hypostome is provided with teeth, which, with the teeth 

 of the mandibles, hold it in place. .The palpi spread outward and apply 

 themselves to the skin on each side, and at right angles to the point of 

 piercing. The Temales leave the host to lay their eggs in some protected 

 place on the ground, such as under a clod of earth, stones, or rubbish. 



The family Ixodidae is sub-divided into two distinct groups or sub- 

 families, the Argasinae or fowl ticks, and tampans, and the I.vodinae or 

 true ticks. 



A. Eostrum inferior, hidden under a frontal ])rojection of the body ; 



no anal plates ; no ])ulvilli at tips of tarsi . . . . Argasinae. 

 AA. Eostrum terminal at anterior eiul of l)ody : a tiorsal shield 



present : tarsi with pulvilli . . . . . . . . Ixodinae. 



Sub-Family AEGASINAE. 



Eostrum inferior (except in the larvae, when it is often terminal, or 

 nearly so, and in the nymphs, when it is sub-terminal, part of it projecting 

 beyond the anterior end of the body), that is, the rostrum is situated 

 on the ventral surface of the anterior end of the body, which projects over 

 it like a hood. The digit of the mandibles is irregularly triangular, wide 

 and swollen at the base ; the inner apophysis is elongated, with the 

 terminal tooth recurved outward, and the process more or less transverse, 

 pointed at both extremities and inserted at about the middle of the length 

 of the apophysis ; the outer apophysis is elongate, provided on its outer 

 edge with two large teeth, similar in form and almost parallel. The palpi 

 are free, elongate, and cylindrical; the articles differing little from one 

 another. The legs are a little unequal in length, the second pair is the 

 shortest, the fourth pair the longest ; six articles, the third and the tarsi 



