ORNITHODORUS SAVIGNYI : EARLY STAGES 587 



main food. It is also common in some of the third class waiting 

 sheds on the South Indian Railway. In South India it is said to cause 

 a particular kind of fever, but there is no reliable information on this 

 point. It can have nothing to do with the spread of Kala Azar, for the 

 parasite fails to flagellate in its alimentary tract, and it has never been 

 seen in any of the houses in the endemic areas in Georgetown in 

 Madras. Drake- Brockman, who recently reported the occurrence of an 

 outbreak of relapsing fever at Bulhar in Somaliland, states that he failed 

 to find a single specimen of Ornithodorits moubata, the species which 

 transmits the spirochaete of this disease in British East Africa ; savignyi 

 was abundant in all the native huts and was probably acting as the 

 carrier. 



The egg of savignyi measures from 1'3 to 1*5 mm. in length and 

 from '8 to 1 mm. in width. It is ovoid in shape and of a dark brown 

 to black colour with a smooth shiny surface. The 

 eggs are laid in batches of from 50 to 100 or more, 

 and hatch in about fourteen days. The larva (Plate savignyi 

 LXXV, fig. 3) is sub-circular in shape, and of the 

 same colour as the egg ; it measures 1'75 mm. in length and about 

 1 mm. in width. On hatching it frees itself from the egg shell, and 

 remains in a dormant condition for about ten days, when it moults 

 and the first nymphal instar emerges ; it never sucks blood. The 

 first nymphal stage (Plate LXXV, fig. 2) is of a light brown colour, 

 and measures from 1*75 to 2 mm. in length and from 1'5 to 1'8 mm. 

 in breadth ; it resembles the adult, having eight legs, and it is extremely 

 active. About two to three days after emerging from the larval state 

 it will feed, taking from fifteen to thirty minutes to become replete with 

 blood. It then drops off, and under natural conditions buries itself 

 in the sand ; the following data give the time occupied by the several 

 stages of this tick. 



9 9 11 . . . . First nymphal instar emerged. 



12 911 . . . . First feed. 



16 911 . . . Second feed. 



21 9 11 .... Second nymphal instar emerged. 



25911 ; . ; . First feed. 



2 10 11 .... Third nymph emerged. 



101011 . . . . First feed. 



141011 . . * . Second feed. 



16 10 11 ... . . Fourth nymph emerged. 



28 10 11 ."'..' . . First feed. 



311011 . ... Second feed. 



7 11 11 .... Adult emerged. 



