MARGAROPUS 



715 



Life-History. — Mar gar opus annulatus begins its life with the egg 

 on the ground, from which the larva emerges, and, gaining access to 

 the host, undergoes its development into nymph and adult without 

 the changes of host described in Eurhipicephalus. 



When the adult female has gorged with blood, she drops off the 

 host and lays her eggs. 



Pathogenicity. — It is the spreader of Piroplasma higeminum, the 

 cause of Texas or red-water fever in cattle. The adult female 

 acquires the Piroplasma and passes it on to the larva, which infects 

 the host. It is also the carrier of Spiroschaudinnia theileri. 



Varieties. — The names of the varieties are: (i) M. dugesi Megnin, 

 1880, in North Africa; (2) M. microphilus Canestrini, 1887, in 

 South America; (3) M. australis Fuller, 1899, in Australia, Asia, 

 Africa; (4) M. calcaratus Birula, 1895, in the Caucasus; (5) M. cau- 

 datus Neumann, 1901, in Japan; (6) M. argentinus Neumann, 1901, 

 in Buenos Ayres. 



Margaropus decoloratus Koch, 1844. 



This is looked upon as a variety of Margaropus annulatus Say 

 by some authors. It is the blue tick of South Africa. 



Morphology. — The clypeal plates in the male end in sharp points, 

 and a caudal appendage is present. The hypostome has six rows 

 of teeth. 



Life-History.— It lives from the larval stage to the adult on the 

 same host. The adult, when fully fed, drops off and lays the eggs 

 on the ground. 



Pathogenicity. — It is a spreader oi Piroplasma higeminum. 



Rhipicentor Nuttall and Warburton, 1908. 



Rhipicephalinae with eyes, inornate, with festoons. Basis capituli 

 hexagonal dor sally, and having very prominent lateral angles with 

 short palps. Coxa I. bifid in both sexes. The male resembles 

 Etirhipicephalus dorsally and Dermacentor ventrally. Coxa IV. is 

 much the largest. There are no ventral shields or plates. Spiracles 

 subtriangular or comma-shaped. 



Type. — Rhipicentor bicornis Nuttall and Warburton, 1908. 



Rhipicentor bicornis Nuttall and Warburton, 1908. 



Synonym, — Rhipicephalus gladiger Neumann, 1908. 



This is an African species living on the horse in the Congo and 

 Central Africa. It attacks and can live on man. Another species is 

 Rh. vicinus Nuttall, 1908. 



Dermacentor Koch, 1844. 



Rhipicephalinae with eyes; base of capitulum rectangular, broader 

 than long. Dorso-submedian porose plate present ; palpi short and 

 thick; stigmata comma-shaped. Male without anal shields. The 



