THE PACIFIC COAST TICK. 185 
Taste LXXXIII.—Engorgement of larvxe of Dermacentor occidentalis. 
Larve dropped engorged — ; 
Date ; " days following application. cota 
Bee Host. ars ee eT! State of engorgement. 
applie 
PP Pct toleas Ln i6.) mi) | bees 
1910. 
May p24 |. Bovine? <<. 0 4-2-5 25 TOOON Ss Opl Pl le S8a On ese ls eae. 52 | Two-thirds to fully. 
Sune, LOl fo: .< Oe miciaicieieietoccie inte os OO xOD |) OMI 27a) lasers Emtcrs [aisle = 33 | Fully. 
June, 21 |. ...< Oe sGs Jee ack oo Be 400K ee Ohi On eOielee Ol es 2 locas ire 2 (?) 
June 27 |.-... WOR or oes cnasonc TOON RTOS) (On| Oee elie Pee hee |e oe 22 | Fully. 
uly #6) uGuinea pig. <2... 500 | Oj O |180 | 60 |206 | 4 |-.-... 400 | Two-thirds to fully. 
Me 8) | BOVANE. 2 .-0- cee --- 5-5 - DOOM TON OnOn ae) 2aleece| 453 6 | Fully. 
July 19 |2+... WOES 22 ehc sae acne = 200) SO FON On| SiG Wey Sree 15 | Two-thirds to fully. 
TING ioe Ley Sree Oras B00) | Gl ON Zu tee wl] ee lyse eaee 4| Fully. 
Aug. 25 | Guinea pig......---.-.- SOO |) cOP Ol | On ROR | aan" i 15 Do. 
TaBLE LXXXIV.—Rapidity of engorgement of larve of Dermacentor occidentalis applied 
to guinea pig at 11a. m., July 6, 1910. 
Period | Percent- Period | Percent- 
Engorged larve Engorged larvee 
ropped Number. ale pay dropped Number. oe Beer 
(tray examined). cation. | dropped. (tray examined). cation. | dropped. 
——— se 
Hours Hours 
July: 95,9 acmis.:...... 6 70 1.5 || July 10,—p.m.... 35 (?) 8.75 
July 9, 2 P: Te sie 10 75 a5 Juilyshl Qasim... 117 94 29. 25 
July 9, 4. OB me = 90 77s 22.5 July 11, 11.30 a. m.. 78 963 19. 50 
July 9, 5.05 p.m... 19 78 4.75 || July 11,5 p.m..... 11 102 2.75 
July 9, 5.3 a Tee 5 784 15 25)|| Suly 12.9 as mu. . = 4 118 1.00 
July 10,— p.m.. 25 (?) 6. 25 
In July, at a mean temperature of 86.82° F., molting began in 6 
days. This transformation appears to require a total effective tem- 
perature of 263° F. 
TaBLE LXXXV.— Molting of engorged larvx of Dermacentor occidentalis. 
Engorged larvee Temperature from 
molted—days fol- dropping to date first 
lowing dropping. tick molted. 
Date engorged larve Host NIM =s Sea eee ee 
dropped. i ber. molted. Aver- 
= Maxi-| Mini- age 
9 
Bp es |) 10) 11) mum.] mum. daily 
mean. 
oak. OB: wl i 
25 /Of2) 32} 100 71.50) 83.47 
Ao 4] 100 73 83. 57 
i ae) eee 1} 100 73 84. 04 
ye] eet eae 10] 97 69 83. 05 
8 Kae |) Sas 4) 97 69 83. 05 
al aes aes 4| 97 69 84. 52 
rei loess P| 7| 98 W305 86. 64 
wll ays é 16] 103.5) 76 86. 4 
Lea | 15} 103.5) 76 86.4 
heel ae 24] 103.5} 76 86. 4 
Peele 19} 103.5} 76 86. 78 
Sey ats = 100} 103. 5! 76 86. 82 
Beers) (Sane = 80} 103.5) 76 86. 82 
Aovallereral eas 2) 103. 5 76 86. 83 
ie | (ea 8 FS . 4] 103.5} 74 87. 75 
6G) eee 4] 102 80 89. 29 
ale Z 1} 103.5) 82 92. 37 
|| aS ee 3} 98 75 87.31 
Eroels craliseie 5} 98 75 87. 31 
| (es 2} 98 72.50) 86.16 
Totale..c 1 Us| ek ey) fee |e | BOT | Dace cmos wae as lees 
1 The larvze which molted on this day are included with those on the following day. 
