LIFE history OF CATTLE TICK. 
L9 
Fable 11. Period of incubation of \fargaropus annulatusai Dallas, Tex., 1906, undi 
various conditions. 
Eggs deiiosited. 
Batching. 
Minimum 
Incubation 
period • 
Eggs deposited. 
Hatching. 
Minimum 
Incubation 
period. 
Dai/<. 
a 5 1 
•' 17 
a 17 
a 39 
a 33 
a 29 
<*27 
a 28 
a 28 
" '_'7 
a 26 
"L'7 
a 28 
6 l>:? 
a 23 
6 23 
/,•_>! 
a 22 
b ._»._, 
a 26 
■ 24 
&23 
c23 
«24 
b 25 
c23 
Aug. 12 
An-- 11 
A.ug. 18 
Aim. is 
Sept. 8 
Sept. f> v. 
Sept. 9 
Days. 
<i 28 
\ | . r. II 
\l.i\ b0 
M;|\ ,1 
6 24 
Apr. 15 
b23 
Sept. is 
a :\-± 
M;i\ 13 
Ail},'. 19. . . 
Sept. 10 
Sept. li 
>• _>:{ 
May 15 
June 12 
Aiil:. 19 
lug. 22 
i 24 
M.i\ 28 
June 23 
Sept. 13 
a 23 
Mj\ 3 
Aug. 22. . . 
Sept. 1 1 
■ 24 
V 
lug. "1 
Sept. L6 
Sep'- 20 
Sep1 21 
6 24 
Aim. 28 
Aug. 28 
Aug. 28 
i, >i 
lulv 5 
July 7 . 
Sept. 23 . 
a 27 
July 18 
Sept. 1 
Sept. 23. . 
• 23 
July 1 1 
Sept i 
Sept. 24 
ft 24 
July 16 
Sept. l 
Sept. 2 
Sept. 9 
Sept. 27 
a 27 
July L6 
Sept. 26. 
July " i 
Oct. 7 
c29 
July i 
.luh 22 
Sept. 9 
( )cl. 11) 
6 :\2 
Julj 20 
\nu'. L0 
Sept. 9 
Sep). 11 
Oct. 15 
Oct. 24 
"37 
July 20 
lug. 11 
■ II 
.fnlv 22 
A.ug. 11 
Auk- 22. 
Sept. n 
Sept. 1 1 
Oct. '26 
b 13 
July :>i . . 
Nov. 5... 
-/ 53 
Aug. 22 
Aug. 23 
Sept. 18. 
Dec. 2.. . 
6 76 
July :<i 
Sept. 18.... 
Dec. 2 . . . 
a 76 
Aug. n 
Sept. t 
Sept. 26. 
Feb. 2'.) 
6148 
A.Ug. 12 
o The eggs were placed in open-bottom tesl tubes in sand in the open air. They were protected from 
the direel r;iys of the sun at all times by a cheese-cloth screen. Up to 11 a. m. they were 
within the shade of the house. 
6 In open-bottom lest tubes in soil exposed to sun ai .-ill limes. 
«• In open pill boxes outdoors protected from sun and rain at all times. 
RELATION OF TEMPERATURE TO INCUBATION. 
In the series of experiments just referred to accurate data on tem- 
perature were obtained. Standard maximum and minimum ther- 
mometers kept in an instrument shelter were used. In Table III 
the records of temperatures are given together with the average 
incubation periods for the various lots of eggs under observation 
during different months. The data show that there is an intimate 
relation between temperature and the period of incubation. The 
shortest average minimum incubation period (23.4 days) occurred 
when the average temperature was highest (80.2° F.). The longest 
average minimum incubation period (137 days) occurred with the 
lowest average mean temperature (53.2° F.). Between these ex- 
tremes there is a graduated correspondence between temperature and 
incubation. 
