342 
Ornithodorus moubata 
hypostome is proportionately developed, some of the teeth being well-de¬ 
veloped and pointed. They are arranged in five transverse rows, the distal 
three 2/2 followed by two 1/1, only the former being functipnal. In the 
succeeding stages, the hypostome increases in size and the dentition becomes 
more complex. At the extremities of the hypostome, the teeth are always 
poorly developed, this being the case at the proximal end particularly, where 
it is difficult to determine the exact number and arrangement. The hypostome 
of the second-stage nymph shows six transverse rows, of which four are arranged 
2/2, a third file commencing at the fifth row. Rows 5 and 6 are but poorly 
developed. 
In the third- and fourth-stage nymphs the transverse rows number about 
8 and 12 respectively, but in the former the functional teeth are still arranged 
2/2 while in the latter a third file becomes well-developed at row 4; in addi¬ 
tion a fourth file commences at row 6. In the later stages the smaller distal 
teeth are arranged in two rows. In the fifth-stage nymph only row 3 remains 
2/2, followed by three rows 3/3 and one or more functional rows 4/4. In the 
sixth- and seventh-stage nymphs, the distal teeth are arranged 3/3 for four rows, 
4/4 for two rows, and then 5/5 for three or more rows, the remaining teeth 
dwindling away posteriorly. 
The dentition of the adult approximates to that of the equivalent nymphal 
stage, the smaller individuals having the lesser number of files and rows of 
functional teeth. 
Commencing with the larva and taking the nymphal stages in order, the 
total numbers of teeth, large and small, borne by the hypostomes of the 
particular individuals to which Fig. 2 relates are 4, 16, 26, 40, 70, 86, 102 and 
104 1 . Males from third and fifth nymphs show 76 and 102 teeth and females 
from fourth and sixth nymphs 78 and 160 teeth respectively. 
(h) The Legs. Fig. 3. 
In Fig. 3 are illustrated the terminal portions of the fourth legs of ticks 
during the successive stages of development, namely the first to seventh 
nymphal stages (normal individuals) and the second to fifth nymphal stages 
(small individuals); of males from the third and fifth nymphs and of females 
from the fourth and sixth nymphs; and also the tarsi of the first legs of 
first and second nymphs. The larval leg is illustrated in Fig. 1. In the latter 
the leg is undeveloped and useless for locomotion, the chitin being exceedingly 
thin and the claws weak 2 . 
The characteristic and diagnostic dorsal humps seen on the protarsus and 
tarsus of the adult are reduced or absent in the immature stages. 
The protarsus of the first nymph carries a slight protrusion which becomes 
more developed at each successive stage, both normal and small, until in the 
sixth and seventh nymphal stages, the hump is as prominent as it is in the 
1 This hypostome may not be typical, as only two individuals were available tor examination. 
2 The larva, like the larva of O. savignyi , is able to free itself from the egg-shell in many cases. 
