THE GOPHER-TORTOISE TICK. 129 
The adult—Among the individuals observed to molt to the adult 
stage there was a predominance of females. The greatest adult 
longevity observed was about 90 days; other specimens lived from 17 
to 76 days. All of these records were made during midsummer. A 
few ticks of both sexes remained active, when kept in tubes in the 
laboratory, for more than 2 months during the summer before being 
placed upon a host. It is certain that with abundant material, placed 
under natural conditions, adults would be found to live much longer 
than those observed by us. 
Several males and 3 females placed upon a tortoise on July 29, 1908, 
readily attached. The first female to engorge dropped 20 days later, 
measuring 24 by 18.5 by 11 mm. Next to Amblyomma varium, 
which has been recorded by Robr (1909, p. 120) as measuring 28 by 
24 by 15 mm., this is the largest tick on record. The second female 
dropped engorged on the twenty-first day after attachment and 
measured 19 by 13.5 by 10 mm. The third female dropped on the 
twenty-fifth day after attachment and measured 19 by 13.5 by 8 mm. 
During the period of attachment none of these females was observed 
in copulation. Upon removing the first female from the bag in which 
the tortoise had been placed it was found apparently in copulation 
with a male which had also dropped from the host. This fact suggests 
the possibility that copulation takes place after the female drops 
engorged. 
Males have been observed to remain attached for a long time after 
the females drop, and this habit accounts for their being more com- 
monly met with upon tortoises. One of the three males which at- 
tached to a tortoise July 29, 1908, remained. on the host 43 days 
after the last female dropped and the other was still attached but 
dead when the tortoise died on January 5, 1909, thus having been 
attached 135 days after the last female dropped, or a total period of 
160 days. The males attached to the margin of the shell as well as to 
the body of the tortoise. It is conceivable that the females may also 
. thus attach to the shell, but if this actually occurs the period of en- 
gorgement must be greatly prolonged owing to the poor blood supply. 
Attempts to secure the attachment of adults to horned toads 
(Phrynosoma cornutum) were unsuccessful. 
LIFE CYCLE. 
Larve may live for at least 95 days during the winter months. 
The period required for engorgement has not been determined. At 
winter temperature in the laboratory at Dallas 86 days passed 
before molting commenced. During this period a total effective 
temperature of 1,583° F. was accumulated. The longest molting 
period recorded was 165 days. The greatest nymphal longevity 
21448°—Bull. 106—12—__9 
