Studies on the biology of the Texas-fever tick. (Supplementary report.)

Issued September 9, 1912,

U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF ANIMAL INDUSTRY.—BULLETIN 152.

A. D. MELVIN, Cuter or Bureau.

BOS

15 se

ST IES ON THE BIOLOGY: OF
*HE TEXAS-REVER TICK.

(SUPPLEMENTARY REPORT.)

BY
H. W. GRAYBILL, D. V. M.,
Assistant Zoologist, Zoological Division,

AND

W. M. LEWALLEN,
Agent in Tick Eradication, Bureau of Animal Industry.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.

1912.

Gass OF 594

—

Book. | 5 (x 3A

Issued September 9, 1912.

U. S. DEPARTMENT OF AGRICULTURE,
BUREAU OF ANIMAL INDUSTRY.—BULLETIN 152.

A. D. MELVIN, Cuier or Bureau.

SEUMIES ON THE. BIOLOGY ‘OF
THE TEXAS-FEVER TICK.

(SUPPLEMENTARY REPORT.)

BY
HoW. GRAYBILL, .D. VM.
Assistant Zoologist, Zoological Division,

AND

W. M. LEWALLEN,

Agent in Tick Eradication, Bureau of Animal Industry.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.
1912.

>”

BUREAU OF ANIMAL INDUSTRY.

Chief: A. D. MEtvin.

Assistant Chief: A. M. FarrincTon.

Chief Clerk: CHARLES C. CARROLL.

Animal Husbandry Division: Grorae M. Rommst, chief.
Biochemie Division: M. Dorset, chief.

Dairy Division: B. H. Rawt, chief.

Field Inspection Division: R. A. Ramsay, chief.

Meat Inspection Division: Rice P. Stappom, chief.
Pathological Division: Joan R. Monter, chief.
Quarantine Division: Richard W. Hickman, chief.
Zoological Division: B. H. Ransom, chief.

Experiment Station: E. C. SCHROEDER, superintendent.
Editor: JAMES M. PIcKENS.

ZOOLOGICAL DIVISION.

Chief: B. H. Ransom.
Assistant Zoologists: ALBERT Hassatt, Harry W. Graysitt, Maurice C. Hatt,

and Howarp CRAWLEY.
Junior Zoologist: WintHRoP D. Foster.

? 5. ar a

oe COPIES of this publication
may be procured from the SUPERINTEND-
ENT OF DOCUMENTS, Government Printing
Office Washington, D.C., at 5cents per copy.

LETTER OF TRANSMITTAL.

U.S. DEPARTMENT OF AGRICULTURE,
Bureau OF ANIMAL INDUSTRY,
Washington, D. C., April 25, 1912.

Srr: In Bulletin 130 of this bureau there were reported the results
of one year’s investigations of the biology of the Texas-fever tick
which were carried on during 1907 and 1908 at Auburn, Ala., by
cooperation between the Alabama Polytechnic Institute and this
bureau. The work was continued for another year, and I have the
honor to transmit herewith a supplementary report by Dr. H. W.
Graybill and Mr. W. M. Lewallen, giving the results of the second
year’s experiments (1908-9). As this information has a bearing on
the cooperative work now being carried on by the bureau and the
authorities of certain States for the eradication of the cattle tick, I
recommend its publication as a bulletin of this bureau.

Respectfully,
A. D. MELVIN,

Chief of Bureau.
Hon. JAMEs WILson,
Secretary of Agriculture.

51506°—12 3

CON AE NTS.

Page
Untrod wetiom.. «23 2ajs si eis). pnd ao ioe 2 ae a ee en 5
Methods of study ......- ae a ey Ob ie ee es eee oe 5
Preoviposition period... \22 722k s 22h a. SE ee ee ee ee 6
Owipositiom period 5. 222520352 see: Ss See Be See eee eee 6
Incubation periods... - oso stie sees lt Seb soe beter aaa ee ke saa Se 7
Hatching period: . oc <%= esses ee soe rc oee tee eae ee ee 8
Longevity period... -. 2... shi. 2655 = oske jee ncte bale eee ee ee See 8
Entire time of nonparasitic development® -2--- 452-442-5242 eee ee eee eee 9
Number of eggs laid and percentageshatched’-:28s2- 322552 25-222 eee eee 10
Comparison of results of indoor and outdoor experiments..........------------ 10
Appendix. 3.22 22.0.s noe.d cath ete sects see eee ammeter 13
A

STUDIES ON THE BIOLOGY OF THE TEXAS-FEVER TICK.

(SUPPLEMENTARY REPORT.)

INTRODUCTION.

During 1907-8 the Zoological Division of the Bureau of Animal
Industry conducted a year’s experiments on the life history of the
Texas-fever tick at Auburn, Ala., in cooperation with the veterinary
department of the Alabama Polytechnic Institute. The results
obtained during the course of those investigations have been pub-
lished in Bulletin 130 of the Bureau of Animal Industry. The work
was continued for another year (1908-9) along the same but some-
what less extensive lines. Mr. W. M. Lewallen, who assisted in the
first year’s work, had charge of the experiments during the second
year.

The second year’s work was undertaken for the purpose of obtain-
ing additional data on the nonparasitic periods in the life history of
the tick, and to determine what variations might take place in the
duration of these as a result of yearly variations in weather conditions.

METHODS OF STUDY.

The methods of study employed were the same as those used the
first year. The indoor experiments were conducted by the use of
incubation tubes, and these were checked by outdoor experiments
conducted in field plots representing natural conditions. The incu-
bation tubes used were the vertical type provided with a glass tube
inserted into the bottom for the purpose of supplying the sand with
moisture, shown in figure 1, Bulletin 130, Bureau of Animal Industry.
The field plots were the same as those used in the first year’s work
(fig. 3, Bulletin 130), being 2 feet square. They were protected from
the intrusion of small animals by means of a wire-netting fence.

In the indoor experiments the ticks were handled the same as during
the first year. Four engorged ticks were collected at the beginning
of each month, and each was placed in a dish by itself, where it
remained until oviposition was completed. At the end of every 24
hours the eggs were removed from each tick, counted, and placed in
an incubation tube marked with the number assigned the tick and
the date the eggs were removed. The dates when the eggs in each
tube began and completed hatching, and when the first and last larvee

5

6 BIOLOGY OF THE TEXAS-FEVER TICK.

died, were recorded, and finally the per cent of eggs that hatched was
determined. The indoor experiments were conducted in an unheated
room, the windows of which were constantly open. ’

In the outdoor experiments two sets of plots were run, one located
in a place shaded a part of the day and the otherin thesun. In each
plot 10 engorged females were placed.

PREOVIPOSITION PERIOD.

The minimum preoviposition period noted was 2 days, which
occurred in the case of ticks collected in August. Ticks collected in
August the first year had a minimum period of 2 days, but the mini-
mum for the year (1 day) was observed in the case of a tick collected
in April. The maximum period (29 days) was exhibited by ticks
collected December 2, and the maximum for the first year (98 days)
was observed in the case of a tick collected November 30.

From the table (last column) it will be noted that the average pre-
oviposition periods increase month by month from the minimum to
the maximum, and then decrease again to the minimum. A similar
increase and decrease were also shown in the case of averages for the
first year’s experiments in the horizontal tubes, but in the case of the
ticks used for the vertical-tube experiments the averages for April
and June were greater than for March.

Preoviposition period—Range and average length of periods.

d Range of | Average Rangeof | Average
Date ticks were | Number} preovi- |ofpreovi-|, Date ticks were | Number| preovi- | of preovi-
collected. of ticks. | position | position collected. of ticks. | position | position
periods. | periods. periods. | periods.
1908. ‘ Days. Days. || 1909. Days. Days.
DANI SNISt aes eee 4 2to 4 3 January dice. ace 4 22 to 24 23
September 1. .___. 4 3to 5 4 February 4.....-- 4 18 to 20+ 19.3
October T= ey 4 5 to 11 758)|||Marchitas 222 4 9 to 16 11.8
November 2..._._. 4 7to 9 Si3| PADI Qe eaee ae 4 9to10| » 9.8
December 2....... 4 17 to 29 25.5) || dtlly 2aec ee sa ae 4 3 F.3:

OVIPOSITION PERIOD.

The longest oviposition period noted was 82 days, observed in the
case of a tick which began ovipositing in January. A tick in the first
year’s, experiments which began to lay eggs in January had an ovi-
position period of 91 days, but the longest period was exhibited by a
tick which began ovipositing in November and continued to lay eggs
for 152 days. The second year the shortest period (7 days), as well
as the longest, occurred in January. The tick giving this: period,
however, deposited only 305 eggs, an exceptionally small number.
The shortest period the first year was 3 days, and this occurred in June.
The average oviposition periods for the first year increased month by
month from a minimum in June to a maximum in November, and

INCUBATION PERIOD. 7

gradually decreased again in the succeeding months. During the
second year the same tendency was shown, the periods increasing
from a minimum in August to a maximum in November, and then,
following a sudden decrease for December, there was an increase for
January and February, after which the decrease was regular for the
remaining months.

Oviposition period—Range and average length of periods.

Range Average Range Average
Month oviposi- | Number of ovi- of ovi- Month oviposi- | Number of ovi- of ovi-
tion began. of ticks. | position | position tion began. of ticks. | position | position
periods. | periods. periods. | periods.
1908. Days. Days. | 1909. | Days. Days.
PAUIPTISE.. a.2 sce a= 4 13 to 15 14.3 || February........ 4 37 to 59 46.8
September........ 4 9 to 18 1458)\) March<=;. 32022 4 22 to 42 33.3
@ctober:...=.3.-.=: 4 13 to 35 Ziel || ePATONU = Fe ee ns 4 26 to 32 29
November........ 4 56 to 63 HOST. Maye so fee ae 4 | 19 to 27 23.8
December... .-.- 4 30 to 42 34,5) |) SUNOS so.c858 2552 4 11 to 19 15.8
Sulyeos5ece0 cae. 4 12 to 17 14.8
1909.
January --...2..-- 4 7 to 82 | 45.8

INCUBATION PERIOD.

The range of the incubation periods of the lots of eggs laid by each
tick is given in the table in the Appendix. The range of the period
for the second year was 18 to 176 days, as compared with 19 to 188
days for the first year. In the table below only the periods from the
time the eggs were deposited until the first eggs hatched in each lot
have been used, and these are referred to for convenience as the mini-
mum incubation periods. The periods to the hatching of the last
eggs in each lot have been included in the table in the Appendix.
The longest minimum incubation period for both the first and the
second year occurred in the case of lots of eggs deposited during the
month of October, being 173 days for the second year and 180 days
for the first year. The shortest period for the second year was 18
days and was observed in the case of lots of eggs deposited during
the month of June, while the lots deposited during the same month
of the first year gave a minimum period of 22 days. The shortest
period for the first year (19 days) was furnished by lots of eggs depos-
ited during the months of July and August.

By comparing the averages in the table below it will be observed
that they increase from August to October and decrease for the re-
maining months, except in the case of the average for July, which
shows a slight increase. In case of the averages for the first year it
is noted that they increase for the months of August to October and
decrease for the remaining months without interruption.

BIOLOGY

OF THE TEXAS-FEVER TICK.

Minimum incubation period—lRange and average length of periods.

Month eggs de- | Number| Range of | Average || Month eggs de- | Nuniber| Rangeof | Average
posited. of lots. periods. _jof periods. posited. of lots. periods. jof periods.
1908. Days. Days. | 1909. Days. Days.
IAT SVIST eee oer 52 20 to 30 23. 10))| Pebruaryo.. ssn 48 82 to 107 95.5
September. .....- 49 32 to 70 AA 80 ]| Marche = esac ecme 170 58 to 90 (455
Octoberae so --ee 49 141 to 173 15 S27)||\ Splilesase= eee 141 38 to 65 47.5
November......- 66 151 to 171 IG Yaad ||P ailbiye Pe eee o 90 26 to 39 30.6
Decemberss-s-s-- 21 139 to 158 T50= Sil MUN s-22-ee sae 47 Isto 26 22.9
i Rui livseroveceree ee 51 22 to 27 24.5
1959. |
Janusnyees: see 70 103 to 141 121.6 |
NM

HATCHING PERIOD.

The maximum hatching period for the second year was 52 days
and for the first year 49 days, and in the case of both years this
period belonged to a tick whose eggs began to hatch during the
month of October. The shortest hatching period for the second year
was 6 days and occurred in the case of a tick whose eggs began to
hatch in May, while for the first year the minimum period for the
same month was 9 days. The shortest period during the first year
(4 days) fell to the month of July. It is noted by referring to the
averages in the table below that those for October and February are
the same, and for the remaining months, with the exception of the
break shown by May, there is a decrease, month by month, of the
averages. In the first year’s work the averages increased from that
for July to the maximum, which ‘is for the month of October, and
decreased for the remaining months, except for a slight increase for
the month of June.

Hatching period—Range and average length of periods.

oe Average Average
Month hatching | Number y are f of hateh- || Month hatching | Number panel of hatch-
began. of ticks. ee dee ing began. of ticks. Arig daaeal ing
eee periods. P * | periods.
1908. . Days. . Days. 1909. Days. Days.
IMU SUIS Ree eee eee 4 17 to 27 DiS b yl vMarcheeys = eres 2 33 to 46 39.5
October-t--225---- 4 47 to 52 50 ATS 32-5 sceic sees 4 18 to 21 19.3
Maye sacciceecises 20 6 to 21 13.8
1909. ig HUIMO Ae Lee Goss 4 | 12 to 18 16
Hebrianry 2 soe oc 1 50 50 ‘oi AS ee 8} i1to21 14.5
} |

LONGEVITY PERIOD.

The longest and shortest longevity periods obtained for the lots
of larvee belonging to each tick are given in the table in the Appendix.
The time to the death of the first larve in each lot is referred to
in the table below as‘the minimum longevity period and that to the
death of the last larve as the maximum longevity period. The
longest maximum longevity period for the second year was 249
days, as compared with 234 days for the first year, and both

TIME OF NONPARASITIC DEVELOPMENT. 9

occurred in the case of lots of eggs which began to hatch during
the month of October. In referring to the averages it will be
noted that there is no regular increase and decrease to and from
the maximum, and the same was noted in the case of the first
year’s experiments. This is no doubt due to the fact that tem-
perature, while it plays some part, is not a controlling factor in
the longevity of larve as it is in the case of the preoviposition,
oviposition, hatching, and incubation periods. The range of the
averages for the months of August to November of the second year
is 104.5 to 213.7 days, whereas the range for the same months of the
first year is 56.2 to 167.4 days. The range of the averages for the
rest of the months of the second year is 63.3 to 77.6 days, as com-
pared with a range of 38.6 to 73.2 for the remaining months of the
first year.

Longevity period.—Range of maximum and minimum longevity and average of maximum

longevity.
|
L | Average
+ Average || c
.|Num-| Range of | Range of 2 Num-| Range of | Range of | of max-
el ae ber | Minimum} maximum Amer Mont ie ber | minimum | Maximum) imum
rece of | longevity | longevity ion he tch of | longevity | longevity | longev-
lots. | periods. | periods. pede. || At lots. | periods. | periods. ity
Pp : periods.
—————E ——<——_ |
1908. Days. Days. Days. 1909. Days. Days. Days.
ATIPUISt. oo. < 6| 16to 36] 99 to 192 121.8 |} April....... 72 6to 60] 31to110 75.3
September... 46 6 to 62 |, 50 to 218 10475) || Maye. oc a o-|) oo0 8to87]| 14to119 77.6
October... .- 31} 13t0 155] 80 to 249 21ST |i, ollne.ccsese 1 LSD 7to8&5| 25 to 139 66.1
November. . 18} 51to0146| 58 to 223 JADU SMIulyesoes oe 56 9 to 48 9 to 106 63.3
August.....] 42 7to 47) 3itolls 64.6
1909. |
March.......| 30) 10to 42} 10to112 71.6 ||
| |

ENTIRE TIME OF NONPARASITIC DEVELOPMENT.

The entire time for each individual tick and its progeny, i. e., the
time from dropping to the death of all the larve, is given in the table
in the Appendix. The longest entire time during the second year
(297 days) was obtained in the case of ticks collected September 1,
while the longest period for the first year (288 days) occurred in
the case of ticks collected October 1. The shortest period for the
second year was 96 days and for the first year 79 days, and both
occurred in the case of ticks collected the first part of June. Tho
averages for the first year increase month by month from June to a
maximum for October, and then decrease for the remaining months,
except that the averages for February and March are the same.
The averages for the second year, given in the last column of the
table below, do not increase to and decrease from the maximum
without deviations, as do those for the first year.

10 BIOLOGY OF THE TEXAS-FEVER TICK.

Entire time of nonparasitic development.

Date engorgea | N eet Range of | Average || Dateengorgea |N rues Range of | Average
females were ean ne ea entire-time of females were prooreed entire-time of
collected, Tae sae periods. | periods. collected. f ae ae Eg periods. | periods.
1908. Days. Days. 1909. Days. Days.
PANISUSTO oe aececee 4 143 to 254 206759) santiany Uesosce oe 4 | 202 to 253 235
September 1.....-- 4| 258 to 297 280 February 4......-. 4 | 204 to 230 218.5
Octoberaeas- see 3 | 271 to 280 219530 |e Marche ase nee 4 185°to 207 198.3
November 2......- 4| 274 to 288 282 ATU Dee teicmeee 4| 139 to 164 154
December 2.....-. 4| 257 to 268 264.8 || May 1 (?)....---- 4 140 to 185 156.5
June ziCe) bee - ae 4 96 to 127 117
SULLY eZ ae eee ene 4] 110to 149 129.5
y

NUMBER OF EGGS LAID AND PERCENTAGE HATCHED.

During the second year the minimum number of eggs laid by a
tick was 305 and the maximum 4,492. The average number of eggs
laid by the various lots of ticks ranged from 1,885. to 4,262. The
lowest percentage of eggs hatched was 3 per cent and the highest
98 per cent. The percentage of eggs hatched in the case of ticks
collected during December, January, and February ranged from 3 to
60 per cent. For the first year the minimum number of eggs laid
was 357 and the maximum number was 5,105, and the averages
ranged from 1,811 to 4,089. The percentage of eggs hatched ranged
from 0 to 98 per cent.

Egg laying and hatching—Total and average number of eggs laid and per cent hatched.

Num- Num-|
Number j|Average |Per cent Number /|Average|Per cent
Date col- bee of eggs number | of eggs oes hee of eggs number | of eggs
Oe cree deposited. | of eggs. | hatched. % Ticks! ‘deposited. | of eggs. |hatched.
1908. 1909.
August 5... 4 | 3,962 to 4,492 4,262 | 48 to 97 || January 1.. 4] 305 to3,723 2,615 3 to 60
September 1 4 | 2,797 to 3) 654 3,252 | 92 to 98 pee ties 4. 4 | 1,993 to 2,970 2,568 | 11to 41
October 1-_. 4 | 1,588 to 3,848 2,768 9to6l1 || March 1.. 4 | 1,380 to 3,361 2,352 | 61 to 93
November 2 AND 215 to 3,329 25075 | o2;torel. || Aprile see 4 | 1,741 to 3,065 2,476} 86to95
December 2 4 a: 496 to 2,201 1,885 | 11 to 27 || May 11..... 4 | 3,181 to 4,178 3,674} 69 to 93
June 22__... 4 | 1,640 to 3,003 2,180 | 60 to 97
ef livg eee 4 | 2,214to3,710} 2,948] 96to98

1 Ticks were collected May 1 and 2. 2 Ticks were collected June 2, 3, 4, and 5.

COMPARISON OF RESULTS OF INDOOR AND OUTDOOR
EXPERIMENTS.

In the next table the dates when the first eggs hatched and. when
all the larvee were dead in each month’s experiments, indoors and
outdoors, are given for purposes of comparison. These dates are of
much practical importance in eradication work when rotation methods
are employed, since the dates when the first eggs hatched are those on
which ticky cattle placed on tick-free land. on dates corresponding
to those on which the experiments were begun will be in danger of
reinfestation, and the dates on which all larve were dead are the

COMPARISON OF RESULTS. ati

dates on which pastures from which all animals have been removed

will be free of ticks.

Comparison of records of vertical tubes and field plots, Auburn, Ala., 1908-9.

Vertical tubes. Field plots.

Date first poet Date first, Deve

Date females were collected. eggs sine Date females were collected. | eggs saa

hatched. ; hatched.
dead. dead.
|
1908. : 1908. |

PATIPTIS GO acc. claioe is cofowwits cas aa Aue SO) Apr: 16) | PA pustio—O2 8: oncnenn eee | Aug. 31} Apr. 3
eptember Ie: 2 oo 5-28-22 Oct | June).25) | September li:2: 5.4... -ee ate | Nov. 23 | May 22
Wietober dl sss ccms cece asses Heb; 25) | July, 8} October 2. .3.-2-5------se-ee|| Apr 19) Junel23

MOVEDIDCR once snes. ose t coe prs (22) Aug. i |) November 25.25... 2.c.-cscese cee May 10 Do.

WIBCAIN DET Antena. cons cacsees mee May 11] Aug. 27 =
‘ 1909. 1909

ona May 10 |'Sept.10\| January fs. -.21-. Melee eee | May 21 | July 30
HebiiATyiA® = Kost Seen cence May 21 | Sept. 22 ; May : Aug. 6
IRIGHELS Sap eto cie noid sia cije'ej Sat May 24} Sept. 24 -| Aug. 25
2\( A eee eer May 28 | Sept. 13 Sept. 11

OVD y 5 ee ee ee June 10} Nov. 2/ Do.
BUNC 2D an ccnc sc ace oss ccessens aualys (2) | Oct= v7 Oct. 2
(CL 2. oe ee a July 28 | Nov. 28 Nov. 13

In comparing the length of time required for the first eggs to hatch
in the indoor and outdoor experiments it was found that for all the
months except March, April, June, and July the time was longer in
the outdoor than in the indoor experiments, the differences ranging
from 1 to 53 days, and for the above-mentioned months the time was
shorter, the differences ranging from 1 to 4 days. The longer time
obtained in the majority of the outdoor experiments may be due in
part to unavoidable errors in observation because of the fact that it
is frequently difficult to determine with certainty when the first eggs
hatch, since they are scattered and some may be hidden from view.
In the first year’s experiments practically the same results were
obtained. For two of the eight months for which comparisons could
be made the time was the same in the indoor and outdoor experi-
ments, and for the remaining months the time was longer in the out-
door experiments, the differences ranging from 1 to 22 days.

In view of the fact that in the two years’ experiments the time to
the hatching of the first eggs was longer in the outdoor experiments
than in the corresponding indoor experiments in all except four
instances, in which cases the differences were comparatively small,
ranging from 1 to 4 days, it seems safe to assume that indoor experi-
ments, if the temperature is maintained near that on the outside,
will be safe to follow in practical work, provided a reasonable margin
of safety be allowed to cover slight variations that might occur in
the direction of a shorter time for hatching.

In the second year’s work, for all months the time required for all
the larve to die was longer in the indoor than in the outdoor experi-
ments, the differences ranging from 2 to 55 days, and the average

12 BIOLOGY OF THE TEXAS-FEVER TICK.

difference being 28 days. In the first year’s experiments similar
results were obtained; in all but one case the periods were longer in
‘the indoor than the outdoor experiments, the differences ranging
from 5 to 42 days, the average difference being 21 days. It there-
fore appears that the time obtained indoors, with incubation tubes of
the type employed, as a rule will be three to four weeks longer than
that occurring under natural conditions. This is what would be
expected, since ticks in tubes are not exposed to the wind, and when
kept indoors are not subjected to the sun, in consequence of which
they will not suffer the loss of body fluids and nourishment that ticks
living in the open will. In addition to this, it is likely that the
humidity in the tubes as a rule is higher than that of the outside
air, which would tend to prolong longevity of the larve. It is be-
lieved that in using tubes such as were employed, the supply of
moisture should not be excessive, the sand simply being kept moist.
Unless this is done it is likely that the life of the larvee may be pro-
longed far beyond that occurring under natural conditions. Unduly
long periods for the death of ail larve, obtained by using incubation
tubes, are safe but uneconomical, requiring the farmer to forego the
use of his land longer than is necessary. It is important that the
periods be ample, but it is likewise important that they be no more
than this, since rotation methods are inconvenient and expensive at
best in the majority of instances.

Jn comparing the time required for all the larvee to die for corre-
sponding months in the indoor experiments for the two years 1t was
found that for all but one month the time was longer the second year,
the differences ranging from 3 to 45 days. The average difference
was 25 days. A similar comparison of the outdoor experiments for
the two years showed that in every instance the time was longer the
second year, the differences ranging from 2 to 36 days. The average
difference was 17 days.

APPENDIX.

Individual records of ticks used in experiments.

Num- | - Er |b Mini- Maxi-
1 leis pe gs ber oe | Eee | ees oy Hees Tieubedon mee za Entire | Per cent
ee ected. | eggs de- =) sea 4 period. - lon- on- time. jhatched.

tick. posited. period. | period. | period. I gevity. | gevity.

1908. Days. | Days. Days. Days. Days. Days. Days.
i eee Aug. 5 4, 492 3 | 15 27 20 to 36 15 116 143 48
Deni $200: 22.5,- 3, 962 4 13 17 20 to 30 12 218 254 97
Doses e=-00:-. 4,489 3 15 24 21to 34 17 141 182 61
a Ae ead02- 4, 104 2 14 18 21to 30 6 207 247 60
Bees: Sept. 1 3, 654 3 16 52 32 to 73 58 249 286 98
Deanse aA: (Ae 3, 604 4 18 51 36 to 75 15 237 279 92
(Serer mas (ene 2,951 4 9 47 3lto 71 21 222 258 93
82-5. eedO=s.--| 2; 197 5 16 50 34 to 70 13 249 297 92
Uesead Oct. 1 1,588 11 LS! ac eceaeen|scences chee [ws cece Nsagocsgea|esecneaad|basosecec
LON se:. sedOces 3, 848 5 35 50 | 141 to 176 10 100 280 19
1 ree ee GO. ces. 2,730 7 20 33 | 151 to 174 10 87 271 9
1 eee tee odor. 2, 906, 8 33 46 | 146 to 174 df 112 278 61
132-22 Nov. 2 3, 187 7 63 18 | 151 to 170 il 107 285 52
AN es * {0 (oe 3,329 9 56 19 | 152 to 168 6 98 274 57
ieee 2002225 3, 167 8 58 19 | 151 to 170 14 110 281 59
IGe-2e3 5 (6 (Ree 2,215 9 61 21 | 143 to 169 18 106 288 71
ie Ses. Dec. 2 1, 858 28 31 9] 114 to 138 18 100 268 27
i eee bee C0s.-e- 1,985 28 35 18 | 103 to 142 8 97 266 17
it eee peed Osseee | ane, 20 17 42 16 | 116 to 144 19 100 268 15
Pi) ee cal bes do.....| 1,496 29 30 9} 115 to 139 8 87 257 11
1909.
74 ESSE Jan 1 3,723 82 21 61 to 119 16 104 243 60
07 ee ECOL. 3, 460 48 18 73 to 120 16 113 253 18
78 ee -do.. 2,970 46 16 94 to 121 21 103 242 17
ec a dos: 305 a 6 | 111 to 117 49 64 202 3
moee ene Feb. 4 2, 601 49 17 53 to 87 17 98 204 33
2600 =-- 220005. 2,970 42 17 68 to 97 21 114 225 36
Bisizjais « Sa(oloeee 2,706 59 14 49 to 87 7 111 230 41
28 nadoe Edo". 1,993 37 12 70 to 90 28 106 215 il
Pee Mar. 1 2,994 - 41 15 45 to 81 25 116 205 79
3052. -- -dol.. 1, 674 28 8 57 to 84 14 107 196 61
cil eee SOON: 3,361 42 14 44 to 77 25 97 185 93
B2isccue Sens ace 1,380 22 8 55 to 77 25 119 207 62
Oust Apr. 2 2, 607 26 7 36 to 49 20 106 164 94
5 Bea Osea 3, 065 32 13 39 to 50 23 95 154 86
Bosc: ats (ee 1,741 27 14 39 to dl 15 101 159 94
SOE eit Edo) 2,491 31 14 35 to 48 11 81 139 95
Siemcee May 11 4,178 27 18 26 to 39 19 118 158 93
pi eeoee —d0see- 4,040 25 17 27 to 37 17 96 140 73
Gh} Sasee BOOE se 3,181 24 17 28 to 36 20 100 143 85
A0 Eos do... 3,296 19 12 27 to 41 14 139 185 69
78 ee June 22) 2,311 19 13 18 to 27 18 80 114 97
Areata Comes 3, 003 11 13 21 to 27 20 95 127 84
AB Secs adOs ee 1,765 15 13 22 to 29 20 62 96 60
C1 eee Kolo pane 1, 640 18 11 21 to 27 9 84 117 89
Cee July 2 3, 452 15 16 24to 27 12 118 149 98
AG... Solas 3,710 17 21 22 to 27 13 94 125 98
Cis eee S1d0%2 3.3 2,214 12 15 23 to 29 20 81 110 96
48.250. eedOn n=. 1 2,416 15 14 23 to 28 a 106 134 98
| | 1
1 Ticks were collected May 1 and 2. 2 Ticks were collected June 2, 3, 4, and 5.
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LIBRARY OF CONGRESS