48 
Adaptation of Ticks 
their host’s retreat and naturally the offspring have a good chance of 
finding the host when their turn for feeding arrives. 
With the Ixodidae the case is different: the fertilized and replete 
females must frequently drop from the host when it is on its wanderings, 
and the offspring may be left stranded in places where they may never 
find a host. The loss of life in nature must be enormous in the majority 
of species, for in most species the larva, nymph and adult must each seek 
a host. The loss of life should be less in those requiring but one host, 
as in Boophilus, where the tick attacks the host in the larval stage and 
undergoes its metamorphosis up to the adult stage upon a single animal. 
The greatest loss of life must of necessity occur in such species as are 
parasitic upon hosts having no fixed habitat. In other cases, owing to 
the fact that the host returns to a burrow, nest, or the like, it is pro¬ 
bable that there may be less loss of life than in the case where an animal 
with wandering habits is chosen as a host. It would be interesting to 
make some numerical determinations of the progeny, especially of various 
species of Ixodidae, with this point of view in mind. 
The large progeny of the Ixodidae secures their survival in nature 
in the face of the many diflficulties the ticks must encounter in finding 
their hosts. In the Argasidae these difficulties are much smaller and 
the progeny is proportionately less numerous. 
Argasidae. 
In the following table I have included all the Argasidae : Argas (A.) 
and Ornithodorus (0.) of which we know the host relationships. The 
list includes 12 species and 1 sub-species: 
Argasidae 
A. persicus 
Hosts and habitat etc. of Tick 
Birds: fowls, ducks, geese, turkeys, ostriches, 
quail, wild doves, canaries. Infests chicken 
coops, etc. 
Man: prevalent in Persia where it infests 
native dwellings. It also occurs in houses 
in Egypt. 
Geographical 
distribution 
(as far as known) 
Africa, Asia, Aus¬ 
tralia, N. & S. 
America. 
A. reftexus 
Birds: pigeons, fowls. 
Man: occasionally entering dwellings from 
pigeon coops, or attacking persons having 
to do with pigeons. 
Europe, N.Africa. 
A. vespertilionis 
Bats: several speciesadults found in the 
abodes of bats. 
Europe, N. Africa. 
* See Ticks, V&xi I, p. 39, where the bats are listed. A variety infests penguins at 
Queenstown, Cape Colony. 
