1900J MICROSCOPICAL JOURNAL. 125 



very little, and on the latter date they undergo a second 

 change, which determines the sex. If the change should 

 result in a female, she still remains attached in the same 

 place ; but if it should result in a male, he immediately 

 releases his hold and wanders about amongst the hair of 

 the animal until he finds a female, with which he mates, 

 attaching himself to the animal just beneath the female. 

 The pair will remain attached to their host until the twen- 

 tieth day, increasing in size but very slightly, the female 

 being a little larger Mian the male. From the sixteenth 

 to the twentieth day the male fecundates the female. On 

 the twenty-first day the female becomes fully mature, re- 

 leases her hold, and falls to the ground; then crawls to 

 some secluded spot and lays her eggs, which in course of 

 time (from three to nine weeks) will hatch, and the life- 

 cycle commences again. 'After the departure of the fe- 

 male, the male tick sometimes remains for several hours, 

 when he becomes detached, falls to the ground, and rare- 

 ly lives longer than two or three days. 



Brisbane is in latitude 27°'28', or within four degrees 

 of the Tropic of Capricorn, whilst all the northern por- 

 tion of the colony is intertropical. The specimens of ticks 

 which have been sent from various localities in Africa and 

 China have generally arrived in England during the win- 

 ter season, the one exception being a yellow tick from a 

 horse in Natal which reached England early in June. 

 This tick laid its eggs, and in hatching the eggs so laid, 

 it was found that those laid on June 6th hatched out on 

 July 14th, or in about six weeks, kept warm meanwhile 

 by being carried constantly in the pocket. The larva lived 

 from two to three months without sustenance, although 

 every opportunity was afforded them, and they certainly 

 underwent no change. On many other occasions the eggs 

 of the cattle ticks from South Africa and China, hatched 

 but always failed to develop further, though the larv® on 

 one occasion survived nearly six months. The complete 



