156 LIFE HISTORY OF NORTH AMERICAN TICKS. 
TaBLE LXIX.—Engorgement of nymphs of Amblyomma cajennense. 
Nymphs dropped engorged—days following 
application, Total 
Date nymphs applied. Host. number 
dropped 
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July 25°a1908- As ae Sey ea a doses OPO EeZe LZ aha He 2ON On| aOeh) On OL 10 21 
Tests ee See A Oe Co Ca ety OF Ob ete 2a On OAs Ou One 14 
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In August, 1909, at a mean temperature of 89.5° F., molting com- 
menced as soon as the twelfth day from dropping. The longest 
time observed to be required for molting was 105 days. During this 
period the mean temperature was about 53° F. An effective tem- 
perature of 558° F. appears to be required for molting. 
The adult (Table LX X).—Of 103 individuals, the sex of which was 
determined at the time of molting, 65, or 63 per cent, were females. 
The greatest longevity among adults observed by us was about 466 
days. This was the record of a single female which, together with 5 
males, was kept on moist sand in the laboratory. These specimens 
molted in September, 1907. The last male died about December 1, 
1908, while the female lived until December 25 of that year. One of 6 
females which molted May 20-26, 1908, lived between 381 and 392 
days. In another instance a male and a female which became 
adult September 11-13, 1909, died between 340 and 380 days later. 
The longevity of 7 other lots of ticks observed during 1908-1910 
ranged from 133 to 366 days. All were kept in the laboratory and 
were not fed as adults. The length of life of males and females 
appears to be about the same. 
Mating, so far as known, takes place only on the host. When 
placed upon a host the males and females attach readily. In one 
case a female was observed to remain in the bag covering the scrotum 
5 days before attaching. However, they usually attach within 24 
hours. Several days, and frequently a week or more, of feeding 
appear to be required before the male goes in search of a mate. In 
our observations the males have remained mated for only 2 or 3 days, 
and often a shorter period, before leaving in search of other mates. 
The shortest period in which a female engorged was 7 days and 
the longest 12 days. One male which was placed on the scrotum of 
a bull July 27, 1909, attached immediately. It was not observed to 
copulate with the females, but reattached several times. It was still 
attached on September 29, a period of 64 days after application and 
41 days after the last female, put on the host at the same time, had 
dropped engorged. During the period while this male was attached 
