188 LIFE HISTORY OF NORTH AMERICAN TICKS. 
among those ticks which have once been attached to a host in the 
adult stage. Hot weather also appears materially to shorten the 
longevity of both sexes. 
TaBLE LXXXVIII.—Longevity of adults of Dermacentor occidentalis. 
Number. 
Date molted or collected. a a All dead. meet 
Male. Female. 
1910. Days. 
Molted: Sully 422-2 coset eee eee ee 0 INO Cts IS=NOVve125511 91 One eee nena 106-147 
Moltedi Aug slOSs 2 5 ease eee 29 ZO ACO AMOI 5. ce satinc eee eee 359 
Molteds Aug a 2 -e scene ee 1) eee te May 275 Lois i ue seee oe is epee ees 285 
Molted {Agi e5 15-20 ac ae ee 2 2 Mary SiO Inf ee ae a ee 266 
IMolted GA ie en aera eee 0 1 | Nov. 38-Dec. 20 -EOLO baa SAE oe 103-125 
Molted, YATE IOY: Van tee ely SE OS eS 2 OM May: 205191 S225 Jyokee as ee eee 269 
Collected, PA DESO. ca pee ee ms 0 1| July 19-Aug. LS NOI: Mae Re ect eee 118-147 
DOs ee Ns oe ee eo ee 1 1G | DUNC h OO RS eae ene 66 
Collected WAwrsbee ena. 552 e se see 2 8 | Aug. 18-31, LOL OE Rear ee ee a es A ee 135-148 
Collected, WASP TNS Be meses Bene 8 4] June 18-July LS 1 O1Qe= eee oe eee 71-101 
Collected, 21ND) C77 ENS ie ge RN Tes 0 Syleouly WSS Anie Ss 1O1ORN a ee soe eeee 82-113 
Collected, May 28) ek. Se i ee 0 2 BONS 2c ee ES ai Pare ey eee ee 51-82 
Collected, OCT AIER  SBe eet ners 6 5 Apr. Op OUTS 2 CRANE ee oe oe ee 166 
Collected; OCES26) eth ee ee cone Aa 0 1} Mar. 20, DR Ee es Aaa gs Deh era and = 145 
Copulation of this species has not been observed before attaching 
to a host. Mating has been seen to take place upon bovine hosts 
any time between one and several days after attachment. In one 
case a female became fully one-half engorged before she was visited 
by a male. One female which was not observed to be fertilized 
became nearly engorged and dropped in about the normal engorge- 
ment period. However, no eggs were deposited by this individual. 
Taste LXXXIX.—Engorgement of adults of Dermacentor occidentalis on bovines. 
Females dropped engorged—days 
following attachment. 
Date females |Num-| State of en- State of en- 
applied. ber. | gorgement. Date attached. Total gorgement. 
2|41!]6 | 71] 9 j10 |17 | number 
dropped. 
1910. 1910. 
A rs Oase seu On Slehtlyy. ton WA prs O bea aeee oes aee Wels LS ae ears dna 1} Fully. 
one-fifth 
7X50) OR ee eee 2) | Winengorged:|| Apres 22) - 32554 eens ee Seal al 1 | Two-thirds. 
Maryi9\s os so 8a ee 10 | Unengorged | May 9........- Ail | eee oe nian) A 5 | O n e-fourth 
to one- to two- 
eighth. thirds. 
May20b asso tj eUnengorgveds| May; 20 sprees || ee |e lene |e 1 | One-half. 
dUNe 4 See ee 3 | Slightly. -..- June Ass oye eae rele es eae 1 | Two-thirds. 
Junew4as.. 232552: ile OO aes: June 15. el Fee esl eal baal ee 1 Do. 
Aug. 26-31 ......- 8 Unengorged. Aug. 31- Sept. Te rs eae ee Ee Pa 2| Fully. 
Septe22)<- sesso YES oe do......| Sept. 24 - ee (eres ested esa ea 1 | One-eighth. 
Males have been observed to remain upon a host for 31 days. 
Females which had become one-fifth engorged upon one host were 
found to attach to another host when given an opportunity. In 
most cases ticks applied to a bovine attached within less than one 
day thereafter, but in a few instances both males and females were 
