= 
24 THE ROCKY MOUNTAIN SPOTTED FEVER TICK. 
Taste III.—Time required for moliing of seed ticks and nymphs of Dermacen- 
tor venustus. 
Seed ticks dropped| Date seed ticks Period Nymphs dropped Date nymphs Period 
engorged. molted. from engorged. molied. from 
dropping |) dropping 
to to 
Date. | Number.| First. Last. molting. || Date. |Number.| First. Last. molting 
1908. 1908. 1908. Days. 1908. 1908. 1908. Days. 
Apr (5 23 | Apr. 20} Apr. 24 15-19 || Aug. 6 17 | Aug. 20 |} Aug. 22 14- 16 
1909. 1909. 1909. 
May 17 15 | May 27 | May 30 10-13 || Sept. 15 5} Aug. 6] Aug. 7 21- 22 
. 
1909. 1909. 1909. 1910. 
Aug. 6 7} Aug. 13 | Aug. 16 7-10 || Oct. 3 3 | Oct. 21 | Mar, 22 18-170 
. 1910. 1910. 
Sept. i 56 | Sept. 7 | Sept. 10 6- 9 || Mar. 23 2| May 4] May 23 42- 61 
1910. 1910. | 1910. 
July 4!) Many.| July 18) July 25 14-21 || Apr. 14 13 | May 24] May 30 40- 46 
July §8!| Many. | July 19 |_..do..... 11-17 || July 21 1] Aug. 1] Aug. 1 11 
July 221 Many. | Aug. 8 | Aug. 11 17-20 | Aug. 1 6 | Aug. 14] Aug. 16 13- 15 
1911. 1911. | _ 1911. 
May 22 110} May 30 June 2 8-11 || Aug. 19 12 | Aug. 31 | Sept. 4 12- 16 
! These records were made in the Bitter Root Valley, Mont.; all others were made at Dallas, Tex. 
’ 
TABLE I1V.—T'ime required for engorgement of seed. ticks and nymphs of Der- 
macentor venustus. 
Date of dropping Date of dropping 
Seed ticks applied. as engorged seed | period Nymphs applied. as engorged | period 
ticks. of en- nymphs. of en- 
gorge- gorge- 
ment. ment 
Date Host. First. Last. Date Host. First Last. 
1908. 1908. 1908. Days. 1908. 1908. 1908. Days 
Apri 2 wOx cde. 22 Apr. 5] Apr. 10 3-8: MADE. lal Oxmo sa ores Apr. 5] Apr. 8 
1909. 1909. 1909. 
daly 12s cee doy23 32. July 15) July 18 3-6 || Aug. 13 | Guinea pig.| Aug. 17 | Aug. 18 45 
1909. 1909. 1909. 
July 28 | Guinea pig.|} Aug. 2| Aug. 4 5-7 || Sept. 10 | Rabbit.....) Sept. 14 | Sept. 15 4-5 
1910. 1910. 1910. 
Aug. 2] Rabbit.....| Aug. 7} Aug. 7 5 || May 24] Bovine.....| May 30 | May 30 6 
Aug. 27 | Guinea pig.| Aug. 29 | Sept. 3 27 || Aug. 13 | Rabbit.....) Aug. 18 | Aug. 20 5-7 
1910 1910. 1910. 
July 191 pitied a July 22] July 23 3-4 || Aug. 19 | Rabbit.....| Aug. 23 | Aug. 28 49 
squirrel. - 
1911. 1911 1911. f 
May 18] Guinea pig.| May 21 | May 24 3-4 || Aug. 172} Ground | Aug. 22} Aug. 27 5-9 
| squirrel. 
1 This record was made by W. V. King in the Bitter Root Valley, Mont. 
on July 21, or the second day after application. 
2 This record was made in the Bitter Root Valley, Mont. 
made at Dallas, Tex. 
Dropping probably began 
Records not referred to in footnotes were 
Those larvee which hatch from eggs deposited by females which 
do not find hosts until late in the spring become engorged during 
July and August and do not molt to nymphs until shortly before 
winter. It is thus necessary for the nymphs which appear late in 
the summer to pass the winter in that stage. These nymphs appear 
in the spring shortly after the emergence of the adult ticks; that is, 
shortly after the middle of March. They continue to emerge from 
