Ticks found on Man and hfk Domestic Animals. Hl'.i 



Ticks are not likely to be confused with mites, except perha])s 

 their larvae, and there are, few mites, none in fact, found on domestic 

 animals, which are likely to be mistaken for ticks. However, ticks 

 can always be distinguished from mites by the presence of a proboscis 

 (hypostome) beset with small backward projecting spines on the false 

 head or capitulum. 



All ticks are l)lood-sucking parasites of mammals, birds, reptiles, 

 and amphibia (frogs, toads, etc.). 



Ticks, which belong to the super-family Ixodoidea, are divided 

 into two groups called families, the Argasidae and Ixodidae. These 

 two families may be readily separated by the presence in the Ixodidae 

 of a scutum (hard chitinous plate) covering the upper surface of the 

 body in the males and fonning a small, round or oval plate on the 

 front part of the body in the females, nymphae and larvae. In the 

 Argasidae the bodies are more or less soft, without any chitinous 

 plate, and the sexes can only be distinguished by the shape of the 

 sexual opening which is situated on the ventral surface between the 

 two front pairs of legs. Other distinguishing characters are to be 

 found in the position of the false head and also the eyes when present. 

 In the Argasidae the false head is situated on the anterior portion of 

 ♦ lie ventral surface, and in the adults and nymphae does not as a rule 

 project beyond the anterior margin of the body. Eyes usually 

 absent, when present, four m number, situated on the lateral margins 

 of the ventral surface of the body; the first pair close to the first pair 

 of legs, and the second pair between the third and fourth pairs of legs. 



In the Ixodidae the false head is situated in front, and is always 

 plainly visible when viewed from above. The eyes, when present, two 

 in number, situated on the lateral margins of the scutum. 



At least four stages occur in the development of ticks, namely, 

 ^'gg, larva, nymph, and adult. In the Argasidae there are usually 

 two or more nymphal stages. 



The eggs vary very slightly in the different species. They are 

 very small (l — 1 mm. in diameter) spherical or nearly so in shape, 

 smooth, and yellowish brown to dark reddish-brown in colour. 



The larvae have six legs, are very small when tliey first hatch, 

 l)ut their bodies become distended when engorged. 



The nymphs of Argasidae resemble the adult females and males, 

 and those of the Ixodidae the females only, except for the absence 

 of the sexual openings and other sexual characters, and, as :i rule, in 

 size. 



Family Argasidae. 



This family contains about seventeen species, of which seven are 

 known to occur in South Africa. Of these, only three need concern 

 us here. Thev are the Fowl Tick, the Tampan Tick, and the Rpinose 

 Ear Tick. 



(1) The Foirl Tick (Argas persicus, Oken). 



This tick is f)ften wrongly termed the Tampan. It is essentially a 

 parasite of fowls, but has also been found on ducks, geese, turkeys, 

 pigeons, ostriches and man. It is extremely common and widely 

 distributed throughout South Africa, and is also found in other parts 

 of the world. 



The nymphae and adults can be distinguished from either of the 

 other two species under consideration here by their shape (compare 



