THE PACIFIC COAST TICK. 185 
TasLe LXXXIII.—Engorgement of larve of Dermacentor occidentalis. 
Larve dropped engorged — 
Date eS days biee in: application. ee 
lary, Host. pheny we eT! State of engorgement. 
applie <2 
sed a | 3 | 4 | 5 | Lar Pe 
/ } 
1910 
May 24] Bovine................- 1,000] 0} 1/38|10| 3]....[.-.. 52 | Two-thirds to fully. 
June 10 }..... __ a a a ect ee RPS ed eS eo a ee ee 33 | Fully. 
June 21 |..... = EO ae ee 400} 0| O| 0} 0O| 2 | re re 2 (?) 
ie a Ss Soe rep) Se Oy OP TE ae eee 22 y- 
July 6] Guinea pig.-.......-..-..- 500 | 0} 0 |130 | 60 (206| 4 400 | Two-thirds to fully. 
Boe Pe OvINe =... 22352 = 5 Se ee Oe Ne ih tk 6 | Fully. 
July 19 |. -.. A ee eee 200}; 0; O; O| 8{| 6] 1 15 | Two-thirds to fully. 
ED Fes oe oa al ea eee 4 Le] calif aN (a el ee] eel eee ae 4| Fully. 
Aug. 25 | Guinea pig............. 50! 0] 0] 0] 0 | 0} 4) i} 15 Do. 
i 
TaBLE LXXXIV.—Rapidity of engorgement of larvx of Dermacentor occidentalis applied 
to guinea pig at 11a. m., July 6, 1910. 
Period | Percent- 
Engorged larve Engorged larve ; 
dropped Number. iederd —< dropped Number. e ie re i 
(tray examined). cation. | dropped. (tray examined). cation. | dropped. 
Hours Hours 
July 9,9a.m...... 6 70 1.5 || July 10,— p.m. 35 (?) 8.75 
July 9,2 p.m.....-. 10 75 2.5 || July 11,9a.m..... 117 94 29. 25 
July 9, 4.35p.m.- 90 77 22.5 || July 11, 11.30 a. m.. 7 963 19. 50 
July 9, 5.05 p. m.... 19 7 4.75 || July 11,5p.m..... 11 102 2.75 
July 9, 5.30 p. m...-. 5 784 1.25 |] July 12,9a.m..... = 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 larvxe of Dermacentor occidentalis. 
Engorged larve Temperature from 
molted—days fol- dropping to date first 
lowing dropping. tick molted. 
#4 Total 
Date engorged larve Num- 
Host. numbe 
dropped. ber. | molted. Aver- 
ad 9 e 
6 r| 8) 9|30|21) 12 daily 
| mean. 
| ’ ’ 
1910. | = fe 
May 27,a.m........... Bovine.. 3gi...|..- | 5 ()| 25] of 2 32 83.47 
Cie, SE ea ee (eee "ie 10. ee ees | ee 4 83. 57 
Se es ee phages | 3. am EY Mies aes Cat 1 84. 04 
a eta! lala F 6a a 3] “4 3] 10 83.05 
oy a do... 31 aes | PR 3} 4 83. 05 
ee ee ae do..... 6| Pi Be a aes 4 84. 52 
og. ly a ee beet GGsc cree a. 5 eel je = eS eel 7 86. 64 
LTT gt eae aia aan aaa Guinea pig... tS) Cy UBis. oh ci 16 86. 4 
a) a eee ee aa. -.. oe Ee 3) Ree Rad gl 15 86. 4 
SO SSR e a RE do... 24\...)... (iy) o4}...f.. |... 24 86. 4 
ge ae eee do. 25 (@)} 1 19 86. 78 
LE A eee ae do. 117} (*)!100 100 86. 82 
LT es ea do. 89] (1)| 78] O} 2)...]...]... 80 86. 82 
8 eee Se do. ay GE RS 2 86. 83 
ie: SS ae Bovine........ 4 uy | oan ee 4 87. 75 
oe {CO ere 0 a ee a 4 89. 29 
Se eee Pe do ee 1 92. 37 
i) 6 aS a SS ae | AR ie RE: aad OR 3 87.3 
ye eee ae 2 ES 6). 5 a ee 5 87.31 
ie ae ; Se 4\. : . a aR 2 86. 16 
Total....|  481|... | ao) Qa eae; eS — 
1 The lary which molted on this day are included with those on the following day. 
