98 LIFE HISTORY OF NORTH AMERICAN TICKS. 
the hosts and their parasites. He observes that in certain species — 
of Ixodes which normally infest wandering animals the hypostomes — 
of the males are strongly armed, while others which attack animals 
with fixed habitats have practically no armature on their hypos- 
tomes. He believes that in some cases the males of these species 
may never attach to the host. With those species which feed upon 
wandering hosts, it is necessary for the males, as well as the females, 
to attach. 
It seems probable that in the species which drop to pass their molts 
greater resistance to high and low temperatures and the power to 
withstand long periods of fasting have been acquired. On the other 
hand, some of the species which have acquired the habit of molting 
‘on the host have lost in this power of resistance. 
As related to protection, the adaptation of habits may be consid- 
ered under accelerated engorgement, attachment to favorable part of 
the host, nocturnal habits, habits while awaiting hosts, and habits 
during molting and oviposition. 
Of accelerated engorgements we have several instances among the 
ticks. These are best illustrated by the fowl tick, which engorges 
within a few hours at the most. Prof. Lounsbury argues that such 
ticks are descendants from forms which remained for days at a time 
on the host. This view is given weight by the habit of the larve of 
the fowl tick, of remaining upon the host for several days to 
engorge. In the cattle tick, Margaropus annulatus, after it has 
become about one-third engorged, which requires a number of days, 
complete engorgement takes place and the ticks drop within a com- 
paratively few hours. In this way the chances of destruction, due 
to removal by predaceous enemies, such as birds, by crushing by the 
host, or by attack by parasites, have been very much reduced. 
Again we find species which have adapted their habits for pur- 
poses of protection by attaching to favorable parts of the body, as 
have Ornithodoros megnini and Dermacentor nitens, which attach 
to the inside of the ears. The species of Hzemaphysalis found 
upon quail, field larks, and other ground-feeding birds in Texas, 
Louisiana, and Florida, appear to attach only to the head, a place 
from which they are not easily removed by the fowl. Perhaps 
the most highly developed habit acquired by ticks for protection is the 
nocturnal habit of species of the genus Argas. Through this habit of 
resting during the daytime they escape detection by the fowls, which, 
upon discovering them, devour them with great avidity. At night 
the fowls go to roost and the ticks have little trouble in finding them 
and engorging at a time when their hosts are inactive; thus the 
ticks largely escape detection and destruction. 
The habit of the immature stages of the gopher-tortoise tick 
(Amblyomma tuberculatum) of burying themselves in the soil after 
