54 LIFE HISTORY OF NORTH AMERICAN TICKS. 
and left the host by the tenth day following attachment. The obser- 
vations of Rohr (1909) on the dropping of the larve do not agree 
exactly with ours. According to his records in Brazil the larvee may 
commence to drop as soon as the second day following attachment, 
the greater number leaving the host on the third and fourth days and 
all leaving the host before the eighth day. 
TaBLE VII.—Engorgement of larve of Argas miniatus. 
Number of larvee dropped engorged—days follow- 
ing attachment.! Total 
: : e number 
Date larvee were applied. es 
Be teal ioe re [ot aga ie ean (MR) ia | REC 
INTs OA IED 7a OV Oy pgs 1 emer ete Res eb 0 OF Ptr le 4 1 0 0 34 
Mie AOo1G07 5000 pean. 2 ets ae LE 0 1 9 6 4 1 0 0 21 
Octoils, 1907, Ml 00 a samss ee a oe eee eee ae 0 0 0 if 1 0 0 0 2 
FUME SG. 1908 BOps Wiss sans os cee ee 0 0 Oo! 48h. ot 2 0 0 64 
Ae e227 L908 O00 ip. Wises. sos soe ee Ie 0 0 18 12 2 0 0 0 32 
Sept. 20; 1909;10.30 p.m. Jess: ocd. ce eee eee £10036.) De aah Sa 5 2 1 95 
Eo eR rot ie RRP eet emcee een) nro 0 LG 4 3 3 0 0 0 1h 
Oct 2251909 10.00 ip amces ons so cette ee 0 0 0 12 17 10 9 2 50 
1 Tn this and all subsequent tables in which this arrangement is followed, the top line of figures represents 
the number of days following attachment or dropping and the figures in the columns beneath represent 
the number of ticks dropped, the number molted, or the number of eggs deposited on the respective days 
following attachment or dropping as the case may be. 
In a test to determine the relative susceptibility of individual 
fowls to tick attack, a Leghorn pullet, a Barred Plymouth Rock 
pullet, a setting hen (part Leghorn) and a sick hen (part Leghorn) 
were placed in a cage and infested with larve. An effort was made 
to place about the same number of larvee on each individual and a 
number were left free in the cage with the fowls. The following 
number of ticks dropped from the different individuals: Leghorn 
pullet 26, Plymouth Rock pullet 27, setting hen 95, and sick hen 13. 
The sick hen died on the sixth day after infestation. A second 
infestation of the three remaining fowls was made on a later date. 
At this time the setting hen was no longer inclined to set. As a 
result of this infestation, about the same number of larve were 
engorged on each of the three fowls. The experiment tends to 
indicate that there is no marked variation in the susceptibility of 
individuals of different breeds. It appears to show, however, that 
on setting hens, which are quiet at the time of infestation and after- 
wards, the number of larvee which develop is greatly increased. 
Up to within a few hours of dropping, the larve are globular in 
shape, but at this time they flatten and assume the typical Argas 
shape, which permits the tick to crawl rapidly and secrete itself 
before being discovered and devoured by its natural enemies. Barr- 
ing accident the engorged larve drop only at night when their host 
is upon the roost. The larval is the only stage in which the species 
remains upon the host for any length of time. Advantage can be 
taken of this fact in preventing its dissemination. 
