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THE FOWL TICK. 53 
The period required for the incubation of eggs in August was 
found to be as short as 10 days, at least 437° F. of effective tempera- 
ture being required for incubation. Eggs kept in an incubator at 
a mean temperature of 89.8° F. hatched on the ninth day, an effec- 
tive temperature of 421° F. accumulating. Rohr states that eggs 
kept at 35° C. (95° F.) hatch in from 8 to 11 days. 
TaBLe V.—Incubation period of Argas miniatus. 
Temperature during incubation. 
| | Minimurh 
Eggs deposited. | Hatching. a Average | ony 
| | Maximum. | Minimum. — eilectber: 
Days. “FF, mae a. | F, 
Tune i | Tuy 11, 1908...-.-.-. | 13 93.5 70.5] $1.44] 499.75 
uly 1, 1908.........-..| July 14, 1908......... 14 93.5 70.5| 81.98] 545.75 
July 9; 1908.......-----| July 4." So 13 94.0 74.0| 83.79 | 530.25 
July 31, 1908.......... Aug. 12, 1908........ 13 99.0 73.0| 86.15] 561.00 
Aug. 5, 1908........-.- | Aug. 15, 1908.......- 11 99.0 73.0| 86.59} 479.50 
emt ees oes | Aug. 16, 1008..-..-.. 10 99.0 73.0| 86.75| 437.50 
Re is 1508.2 | Aue. 30, 190822222 13 93.0 7a3| ss48| 526.95 
Aug. 24” 1908.....1.12_| Sept. 5,'1908...02.2) 13 94.5 75.0| 83.40| 525.35 
Aug. 31, 1908......._.- Sept. 11, 1908.......- | 12 | 7.5 74.5 | 84.41 | 496.95 
oe ee Sf ieee eel ee 
“eS Sk, See soe ifs 9. i> / i200. 
ee Nov. meee: 40 7.0 -34.0| 65.20] — 887.00 
Se | Nov. 7, 1908........- 31 7.0 45.0}  67.00| 743.00 
Nov. 7, 1908.......-._- | Jan. 22, 1909....22.2. | 77 82.0 17.0 59.50 | 1,141.00+ 
Nov. 9, 1908........._. Feb. 23, 1909.......- 107 85.0 17.0} 59.50 | 1,582. 00+ 
Nov. 23, 1908.........- Rat ae eee | 93 85.0 17.0| 58.50} 1,339.00+ 
May Tee | May 20, 1900-2. 20 95.0 51.0] 76.50 | 671.00 
pt. 20, 1909.......... et. 15, 1909.......-- 95.0 52.0) 74.50] 860. 
fet. 2, 1909-2 2 Oct. 24, 1909 | 23 94.0 52.0] 73.10] 693.00 
Oct. 6, 1909............ Nov. 3, 1909.......-- 29 92.0 51.0 71.60} $31.00 
The larva (Tables VI, VII, VIIT).—Seed ticks kept in pill boxes 
in the laboratory at an average daily mean temperature of 61.9° F. 
have been found to live as long as 164‘days. During midsummer 
the longevity is about two months. 
TaBLE V1.—Larval longevity of Argas miniatus. 
Days | Days 
Date hatching Date all larve from | Date hatching Date all larve from 
began. dead. hatching | began. dead. hatching 
to death. | to death. 
mr 9, 1908.....-..| Oct: 20, 1908... ...: G3:.| Now: 3; 1908.62: .225 Mar. 22, 1909. ..... 140 
Sept. 8, i | eens Dec. 25, 1908... ... 108 | Nov. 9, 1908.......... | Mar. 27, 1909.....- 137 
Sept. 25, 1908. ..... Jan. 24, 1909....... 19) ) Dees A008 eo 2: | Mar. 17, 1909...... 105 
Oct. 15, 1908. .....- Feb. 24, 1909...... 132 | May 18, 1909.......... July 15,1909... .-. 77 
Oct. 17, 1908....... Mar. 30, 1909... ... 164 | May 24, 1909.......... | July 27, 1909...) 64 
ore. 21, 1908. .=.-. Mar. 27, 1909.....- 147 
At a temperature varying from 18° C. (64.4° F.) to 27° C. (80.6° F.) 
Rohr has found individual larve to live as long as 65 days. 
Ordinarily larve do not commence to drop from the host until the 
fourth day following attachment, although one may occasionally leave 
the host a day sooner. All the larve which we observed engorged 
