G. H. F. Nuttall 
69 
our knowledge of the life histories of the species, and the records are as 
a rule wanting in essential details and precision. Although all the data 
required have not been collected it appears desirable to publish these 
observations as they stand. An attempt has been made to make the 
records as complete as possible and to arrange the material in a uniform 
manner, so that certain data can readily be found by reference to the 
protocols. Of the remaining species, Ixodes putus, canisuga and 
hexagonus, little or nothing has hitherto been known regarding their 
biology. Wherever the work of other authors has been cited, full credit 
has been given them for what they have accomplished; in some cases 
a note incorporating all the information contained in their papers is 
given. 
It is essential that ticks should be raised experimentally, not only 
that we may become familiar with their behaviour as parasites but with 
the part they play in pathology. The future will show that it is only 
by raising them under laboratory conditions that we can determine their 
degrees of variation in structure and learn to be familiar with their 
immature stages. At present the systematist can scarcely recognize 
more than a few immature forms of well-known species and undoubtedly 
differences due merely to individual variation have led to the creation of 
bad species. 
Methods. 
It may be useful to other workers to know about the methods we have 
employed for I’aising ticks. 
Infesting the host and collecting replete ticks. When cattle were used 
as hosts the ticks were most commonly placed upon the ears, the latter 
being enclosed in bags. A bull would have been more convenient, the 
bag being placed about the scrotum. A ram has been used repeatedly 
for feeding ticks upon the scrotum, the replete ticks falling into the bag 
when they abandon the host. When ticks attached themselves in other 
situations, either on cattle or sheep, we had to rely on chance for their 
recovery in a stall which was kept as clean as possible. When dogs or 
the jackal served as hosts they were placed in specially constructed 
metal cages shaped like a barrel placed horizontally upon an insulated 
stand, one end of the barrel being open but guarded by a metal grating ; 
a similar grating served as a floor for the animal to stand upon. 
Smaller animals were placed in appropriate metal cages standing in 
large whitened trays, around the outer margins of which there was a 
gutter filled with water. By cleaning and inspecting the cages 
