80 LIFE HISTORY OF NORTH AMERICAN TICKS. 
A nymph molted in June in 25 days, when the mean temperature 
was 82° F. A total effective temperature of at least 955° F. was 
required. Thus an exceptionally high effective temperature appears 
to be required for the nymphal molt. There is also a considerable | 
variation in the periods in which the nymphal molt takes place. 
The length of the molting period of nymphs which become males is 
practically the same as that for nymphs which transform to females. 
TaBLeE X1X.— Molting of nymphs of Ixodes scapularis. 
[g¢=Male. 9=Female.] 
f : : Temperature from 
Nymphs molted—days following Number : 
dropping. molted. dropping to date 
Date en- first tick molted. 
gorged : Num- 
nymphs Host. | ber. 3 ; ‘ > an 
dropped. | lalla | ae | #22 
25/30] 34) 36}38| 42) 43] 50} 62) 56/9 | 8/8) BS |] 85 538 
a = > 
sialeo|a8 | sf |< 
a) ES SS eee ee eee ee eee eee 
| oT oo, | ee 
June 23,1908 | Bovine.. 1 fie #2 Pe HL lee leet sere sees et ed 1 1 95.0 70.5 | 82.74 
June 25,1908 |...do....- 33 | ice |19 ie clears 19}... Ley Ly 2 3) “Bh205] Oko S2age 
June 26,1908 |...do..... 1 TO ae lsaafete a> «| reaci foe eee 0} 1 1] 94.0] 70.5 | 82.20 
June 27,1908 |...do..... 4 EPs IL OU ST ese one Litleose| arly Lede) 0520" Oona 
June 28,1908 }...do..... pg Re ae (eee Fares Ot ee | eee ee stp) Ol) “Deel 2.9550.) -7OlSyip a Saesey 
July 15,1908 |...do..... 1 Bact ees ee od Ne ee (Vathve 1} 99.0] 73.0] 85:28 
July 16,1908 |...do..... 2 Sates Moti os bese WO eee oe 1 1} 2} 99:0:)' 73.0 |+ $5.76 
Total... /.--.-----. Fg Daa RH es 2 ara “s| 8128 | 
| 
The adult—The longevity of unfed males and females has not been 
determined owing to the limited supply of adults at hand. When 
removed from a host the adults do not live long unless kept quite 
moist; even the engorged females die unless they are kept under 
such conditions. 
Males and females which would not attach when placed on a host 
September 1 attached readily when given an opportunity 4 days 
later. The following day they were found mated. On the morning 
of the second day the males had detached, but in the afternoon they 
were again paired. One male remained with a female for 4 days, 
while others changed to a second mate during this time. Our obser- 
vations indicate that ordinarily mating is not continuous upon the 
host. It appears that mating may also take place off the host. We 
have observed an engorged, unattached female and an unattached 
male in coitu shortly after they were taken from the hair of a hunting 
dog. In the course of this act the mouthparts of the male are intro- 
duced into the genital pore of the female. 
A partially engorged female, collected in Florida, engorged and 
dropped on the seventh day after attachment to a bovine at the 
laboratory. A female applied to a bovine September 1 attached 4 
days later and remained attached until September 25, when it was_ 
rubbed off by the host. At that time it was about one-third engorged, 
measuring 4 by 2.2 by 1.4 mm. A second female attached at the 
——— oe 
