Ais^XALS OF THE TkA^^SVAAL MuSEUM. 



75 



(except those of the first pair)/show a false articulation at a distance from 

 their proximal ends, equal to their diameters ; the coxae are contiguous, 

 or almost so ; tlie tarsi are not provided with judvilli. Tlie integument is 

 of a colour varying from dirty yellow to dark Ijrown ; there are no 

 -chitinous plates^ either as dorsal shield or ventral or anal plates ; the 

 integument instead is adorned with pits, furrows, and sculptures of various 

 forms. Tlie stio-matic ])lates are situated between the last two pairs of 

 legs, laterally and dorsally of the coxae. The sexual pore is ventral, median, 

 transverse, and situated opposite the intervals between the first two pairs 

 of legs ; in the male the pore is narrow, almost as loug as wide, and semi- 

 lunate ; in the female the pore is an elongate slit almost as wide as the 

 rostrum, with its e.dges parallel ; otherwise the two sexes are almost 

 indistinguishable from each other, except tliat in general tlie males are 

 considerably smaller than the females, and do not distend to such an 

 extent after feeding. The nymphs are very simihir to the adults, except 

 in lacking the sexual openings. 



The members of this family are parasitic m mammals, but especially 

 on birds. There are two genera, Argas, the fowl and bird ticks, and 

 Ornithodoros, the tampans and sand ticks. 



Adults and Xyinp/is. 



A. Body usually fiat, and thin at the edges ; no deep furrows on the 

 ventral sui'face ; no eyes . . . . . . . . . . Argas. 



AA. Body tbick at the edges ; ventral furrows present ; eyes present 

 or aliseiit . . . . . . . . . . . . 0 niit/iodoros. 



Larvae. 



A. Body thin ; larvae active . . . . . . . . . . Argas. 



AA. Body thick and swollen ; larvae not active, or only so for a short 

 time, at least they never feed . . . . . . Ornithodoros. 



Genus AKGAS, LATEEILLE. 



Argas, Latreille (1796). 



nil ijuclio prion, Hermann (ISOrt). 



Argas^ Latreille (Neumann, 1896). 



Body fiat ; general contour usually oval with rounded extremities, 

 sometimes orbicular, the anterior extremity narrower than the posterior, 

 widest behind the fourth pair of coxae. Anterior end of the body projects 



• beyond the capitulum like a hood. Lateral edges thin or a little thickened. 

 Integument without papilla?, but somewhat roughened by irregular zigzag 

 wrinkles or folds, which are absent only at certain points, occupied by 



, nearly circular pits ; these are shallow, more or less numerous and 

 scattered, the laroer ones form radiating series on both dorsal and ventral 

 surfaces, of which the median posterior row is longest. Eyes absent. 



This genus includes the f<^wl tick and bat tick. They are easily 

 recognised by their fiattened bodies, which cause them to look not unlike 

 bed-bugs. The edges of the body are very thin, and formed by a series 

 of folds or rectangular plates. On both upper and lower surfaces there 

 is a system of shallow shiny pits, wuth raised edges, grouped into lines 

 radiating from a central point. 



