608 MEDICAL ENTOMOLOGY 



teeth. Male with caudal appendage well developed ; adanal plates 

 indented on their posterior borders ; accessory plates pointed on their 

 postero-internal borders. Female with scutum small and short ; eyes 

 situated a little anterior to its middle. Porose areas sub-circular. It is 

 found on the horse in Japan. 



Variety argent inns, Neumann. Hypostome in female with six rows 

 of teeth ; scutum and capitulum small ; porose areas elongated transversely. 

 Legs relatively short. Male unknown. This variety is found in Buenos 

 Ayres. 



Margai'opus loitnsburyi, Neumann. Male. (Plate LXXVIII, fig. 1.) 

 Palps with second and third segments not forming an external projection. 

 Legs with well-developed long, broad segments ; claws inserted at a dis- 

 tance from the spur. Hypostome with eight rows of teeth. Adanal 

 plates straight and awl-like, joining each other anterior to the anus to 

 form an uneven plate. Accessory plates wanting. Caudal appendage 

 well marked, and bearing tufts of hairs. Coxa I undivided, with two 

 very small spurs ; on each of the other coxae there is a small spur. 

 Legs increase in size from before backwards; the segments of leg IV 

 are greatly dilated and form deep angles. Length 3'9 to 4'3 mm. 

 (Neumann) 



Female (fig. 2). Body a little broader in front than behind. Porose 

 areas large and oval, twice as long as broad. Legs with cylindri- 

 cal segments, dilated at their distal extremities. Maximum length 16 mm.; 

 maximum width 10 mm. This tick is found in Cape Colony and the 

 Orange River Free State, on cattle and horses. 



Ticks of the genus Margaropus are of considerable importance, for 

 annulatus, austral Is and decoloratus are the invertebrate hosts of Piro- 



plasma bigeminum ; decoloratus in addition transmits 



Relation to Disease : ,. 7 ,, ., . , ,,, r> L- 



... p Spirocahaeta theilen to cattle. P. bigeminum pene- 



trates the egg of the tick and the larvae which hatch 

 out later are infected with the parasite ; they, as well as the nymphs, 

 are infective. It is very probable that parasites ingested by the larvae 

 are transmitted later by the adults. 



The life processes of the ticks of the genus Margaropus differ from 

 those of the rhipicephalines, such as evertsi and bursa, which only have 

 two hosts, as they pass their complete life histories on one animal, 

 the nymph and females remaining at the same spot at which the larvae 

 attached themselves ; the males, however, move about in search of the 

 females. As far as is known all the varieties of annulatus described 

 above behave in the same way. 



