66 LIFE HISTORY OF NORTH AMERICAN TICKS. 
this same habit in observations made at an infested dairy in the 
vicinity of Corpus Christi, Tex. The cracks and crevices in front of 
the mangers were examined and numerous adults (both alive and 
dead), eggs, and larve were found. The greatest number were 
secreted several feet above the mangers. By crawling up in this way 
they find the dry quarters that appear to be required for development. 
Such a habit is of advantage to the larve in finding their way to the 
ears of the host, as cattle using infested stalls or rubbing against 
infested trees and fences undoubtedly pick up large numbers. 
Our records show that nymphs may molt as soon as the sixth day 
after dropping. The spines characteristic of the nymphal stage are 
shed with the molted skin and are not found upon adults. 
The adult (Tables XII, XII1).—In the adult stage this tick never 
engorges blood, a habit, so far as known, unlike that of any other 
species of tick. During the long periods of feeding as a nymph, 
development appears to take place sufficiently so that oviposition 
commences directly following fertilization, which may be as soon 
as 8 days after molting, or possibly sooner. The females may live 
for long periods if they do not find mates; thus a female collected 
July 22, 1905, and kept isolated in a small pill box (molting 6 days 
later) lived until January 22, 1907, a period of approximately 18 
months. During this period no eggs were deposited. The longevity 
of 13 females varied from 66 to 260 days with an average longevity 
of 138.5 days. Males were placed with these as soon as the females 
became adult (molted). The longevity of these males varied from 77 
to 166 days with an average of 100 days. These males and females 
were the largest individuals selected from a considerable number of 
collected nymphs. The greatest adult longevity observed in our 
investigation exceeded 638 days. 
As in other argasid ticks, the sexes may be readily distinguished 
by the shape of the genital opening; in the female it appears as a 
transverse slit, while in the male it takes the form of a crescent. 
Mating.—The species has frequently been observed in copulation 
in pill boxes. We have never observed the proboscis of the male 
inserted in the vulva as occurs in Argas mimatus, although this prob- 
ably occurs. Christophers, who has studied ticks in India, states 
(1906, p. 9) that with Ornithodoros savignyi when placed in glass or 
porcelain vessels, a rapid tapping sound is sometimes heard which 
appears to be due to a vibration of the hinder portion of the body. 
We have frequently heard a tattoo-like sound made by adults of O. 
megnini kept in pill boxes and have considered it a sexual call. 
Upon removing the cover from the boxes the sounds have stopped 
and we have never observed a tick during the process. It appears 
that this habit is characteristic of the genus. 
