2. The result of various external conditions on the life of the 
larva; and also the duration of life when the larva was 
subjected to total starvation. 
The relationship of the desired data to the question of quarantine 
will be readily recognised, since they should furnish facts on which a 
reasonable period of quarantine could be based, such period varying, 
as has now been ascertained, according to the time of the year, and also 
to certain climatic conditions. 
Four stations were established towards the end .of 1917, viz., at the 
University, Brisbane, as head-quarters; Woolooga (on a tributary of 
the Mary River); Toowoomba (on the Darling Downs); and West 
Burleigh (on the coast), each under a trained observer. Only three 
were provided for in the original plan, but the generosity of Mr. OC. J. 
Booker permitted the establishment of the fourth station—Woolooga. 
The work was carried out on similar lines at all stations, and as large 
numbers of ticks as possible were used, so that the results obtained 
might be more reliable, Every engorged female received was numbered, 
its date of dropping or removal from the animal noted, and the period 
before egg-laying began and that during which egg-laying took place 
were both carefully recorded—also the hatching period, the date on 
which larvee began to die off, and the date by which all the larvex of a 
brood were dead. No food was supplied. These experiments were 
carried out in tubes in shade, while a number of ticks were regularly 
placed in small grass plots under natural conditions, and similar periods 
noted. 
Thus it was hoped to ascertain the various periods (maximum, mini- 
mum, and average) of the non-parasitic stages in its life cycle, and 
particularly to determine the maximum and minimum periods of time 
between the dropping of the engorged female tick and the death of its 
offspring which do not gain access to a suitable host. 
Plots were laid down whenever ticks were available, but during 
winter and early spring it was commonly a matter of difficulty to obtain 
any at all. 
The present account of. the investigations is of the nature of an 
interim report, since it deals only with one portion of the work, viz., 
the non-parasitic stages in the life-cycle of the cattle tick, as observed 
at the various stations, Brisbane, Woolooga, Toowoomba, West Bur- 
leigh, when under field conditions, 7.e., in experimental grass plots. 
The following table shows the minimum period (Period A) elapsing 
between the dropping or removal of the engorged female during the 
month and the earliest hatching out of larve from the eggs laid by it. 
The results tabulated are the lowest obtained from plot experiments 
during the period of the work (November, 1917, to May, 1919) for the 
particular month set down. Climatic conditions are not indicated in 
this report. . : 
The paddock (if tick-free to begin with) would probably not be 
infective for cattle during the periods mentioned. 
421 
