THE RABBIT TICK. 95 
The adult (Table XX VITI).—The longevity of adults of this species 
is probably equal to that of any other ixodid tick. In a tube which 
contained a lot of about 24 adults which molted from nymphs 
shortly before September 29, 1909, the last individual, a female, died 
May 10, 1911, having lived at least 588 days. A male in another lot 
which molted to adults between February 22 and March 29, 1910, 
lived for 403 days. In a third test a female in a lot which molted 
between March 23 and April 4, 1910, died on May 10, 1911, after a 
period of 401 days. One male ina lot of about 6 males and females 
which became adult April 15, 1908, lived for 395 days. The longevity 
of several other lots of ticks upon which the date of molting was 
recorded ranged between 109 and 355 days. These lots became 
adult in the spring and early summer months. A longevity of from 
17 to 167 days was observed in the case of 10 lots of adults collected 
on hosts during 1909 and 1910. 
Considerable difficulty has been met with in getting females to 
engorge. Although males and females have attached in conspicuous 
places on the ears of tame rabbits, we have failed to observe them in 
copulation. A small female dropped in 17 days, but the only female 
which attained full size required three weeks for engorgement. 
The last individual, the engorgement of which is recorded in the 
following table, was placed on the host without males. Mr. George 
Wolcott, who observed this engorgement, found that it attached in 
less than half an hour. It remained for at least three weeks before 
any appreciable engorgement took place. In the last three days 
engorgement was very rapid. 
TaBLe XXVIII.—Engorgement of females of Hemaphysalis leporis-palustris. 
Female | Period 
Adults applied. | Host. dropped jof attach- Size engorged. 
engorged.) ment. 
Days. 
Ta ONS See ory tao cis onc ay aimn cstetomise nt Rabbit....| July 25 17 | 6 by 3.5 by 2.5 mm. 
DON et ess Pech) cea ha eee T ACs (operas Ee July 29 21 | 10 by 6 by 3mm. 
1D 0) 36 Ne ee IEE SS ets ie i ES Eee GOs cee Aes co 26 | Scratched off. 
Pars was VORUSS tok... ee - Be et en eae Ae Bee 0 koa ae Feb. 18 35 | Fully engorged. 
LIFE CYCLE, 
This tick may commence to oviposit as soon as the fourth day 
after leaving the host. The largest number of eggs deposited by an 
individual was 2,240. The eggs have been found to hatch in 22 days. 
A total effective temperature of at least 902° F’. is required for incuba- 
tion. Larve have been found to live 258 days. _ They may engorge 
and drop in 5 days after attaching to a host. Molting of larve may 
begin in 18 days. A total effective temperature of 463° F. appears 
to be required for the transformation to nymphs. Nymphs may live 
