Pha 
THE BLACK-LEGGED TICK. 79 
3 The larva (Tables XVI, XVID).—Larve which hatched in March 
have lived for 24 cain tlie in the laboratory and then attached to a 
H bovine and engorged. Their longevity is undoubtedly considerably 
F longer than this period. 
_ Larvee were found to engorge and leave the host as soon as 3 days 
_ after application, the longest period required being 9 days. 
TaBLE XVI.—Engorgement of lurve of Ixodes scapularis. 
Larve dropped engorged—days fol- Total 
P | lowing application. num- 
Date larve applied. Host. | ber 
dro 
Py 1);2|3] 4 5|6/]7)]8]|9] ped 
| Pia 
ANE fo oso wee vweweaie ge wawe ses By BETS Bovine | 6-5 Or)-38-set ST 0.1 O17 .0.1. 0 35 
OS EE Oe Eee ere reen® ae do 0] O| O} 1] Of} 7] 22] 3] 1 34 
EE, SOM set hn Sy ap ok ow => ee gone mans ane + be 4 do Ler ah wie Of B | 0}. 8) @ 3 
= RRR IRC HE: hy ee RO SD do 0| 0] 1| 0 0 0} 0} 0} o| 1 
_ In May at a mean temperature of 77.19° F. engorged larve have 
commenced to molt on the twenty-third day, the last to molt shed- 
ding its skin on the thirty-first day. Thus an accumulated effective 
_ temperature of 786° F. was required. 
TaBLE XVII.— Molting of larvz of Ixodes scapularis. 
| 
Temperature from 
Larve molted—days follow- | ditties tek! Weta 
| | | 
| | | | 
, | ing dropping. | first tick molted. 
| Total 
Date engorged larve | F Wain meds ot ot LF OS reverse ETE peat 7 
ial) molted. . -. Average 
| Ey 24| 25 '25|27|28| 2930) 2 axe | Mint | daily 
| | Poe aa "mean. 
em ee ed | 
ee Se ee eee ee ee ee ee eee ee ss Se Eee eee 
| au | oP. | oF. | oF. 
May TLL) a ae ae Bovine.. 18 OVE A1S 1S TROT LTO 14 | 88.50 63. 00 Zi. 
May 10, 1908...........|.-. o....| 2+4/213}/5/1/1}0]slolo 20 | 87.50 | 65.00| 77.19 
US a ers ae Bi. 5 0;3/;21;0/0(10);0/0);0 5 | 88.50 | 65.00 77. 62 
May 29, 1908...........|... a 4 |0|11]0| Othersdead.| 0| 0 1 | 91.50 | 69.00 72 
many 30, 1908...........].-. oe: . 3 2;0/;0/;/0/0/0/0/0);1 3 | 91.50 } 69.00 80. 86 
ai 1008...........|--. $1) 3 lololololololololi4 1 | 91.50 | 69.00| 80.90 
aie. .......-:-|.. “Eo 2 /1/o0lololololololo 1 | 97.00 | 47.00| 86.64 
The nymph (Tables XVIII, XIX) ity TERR of sil which 
molted in June lived 2 months 3 in the laboratory and then attached to 
host. Nymphs engorged and dropped as soon as the third day 
after application, the last to drop leaving the host on the eighth day. 
TaBLE XVIII.—Engorgement of nymphs of Ixodes scapularis. 
Nymphs dropped engorged—days | Total 
following application. num- 
Date nymphs applied. Host. | ber 
drop- 
| 1/2;3;4]5}]6)] 7] 8) ped. 
BETES « Salon's 4540 5a Gwaun eaian Bovine..| 0}; 0} 1] O} 3] L] 4] 2 11 
NS a i rae | ae do....| 0} O}| O| OF} 1] L] OO} O 2 
ES A adlin wicmnk <>'s ve cau ee ksdes cedars do....| 0/ 0} O| O}| 27 O} OF O 2 
