THE SPINOSE EAR TICK. 65 
The larva (Tables XI, XII, XIII).—The seed ticks of this species 
soon succumb if exposed to moisture such as is required by the ixodid 
ticks when kept in tubes on sand. When kept in dry pill boxes after 
hatching some have died in a few days while others have lived nearly 
a month. On April 22, 1910, about 2,000 eggs deposited between 
April 8 and April 22 were placed in a tube out of doors. On May 19 
most of the eggs had hatched. OnJuly 27 only 5 or 6 larve remained 
alive, and the last tick died August 3. Thus it appears that a period 
of 103 days may elapse from the deposition of the eggs to the death 
of the last larva. The larve usually remain in a dense bunch when 
not disturbed, but if aroused they become very active. Upon 
gaining access to the ear they attach to the sides of the concha. 
As is shown in Table XII larve may molt as soon as the seventh day. 
In the five infestations recorded all had molted by the twelfth day 
after application to the ear. The appearance of the engorged larva 
has led several authors to speak of it as a pupa-like stage. It is not 
a resting stage, as the engorged larve move about when detached 
from, the host. However, there may be a brief period of quiescence 
immediately prior to molting as occurs in the case of most ticks. 
The nymph (Tables XII, XIII).—The nymphs engorge very slowly 
and require a comparatively long time for development. In feeding 
they usually produce scabs, which peal off in layers beneath and 
about the tick, thus requiring occasional reattachment. There 
appears to be a great variation in the period that the nymphs remain 
upon the host. In our observations the first nymph to leave was 
found in the bag attached to the ear on the thirty-first day after 
_ attachment as a seed tick or about three weeks after the larval molt. 
Others have remained attached to the host for nearly 7 months (209 
days) and would undoubtedly have remained longer had it not been 
that the host was unwittingly sprayed with naphtholeum by an 
assistant. Our observations indicate that nymphs when well en- 
gorged may at times be dislodged by violent exercise on the part of 
the host. 
In order to determine whether the cotton bags tied to the ears 
influenced the ticks in leaving the host, the bags were removed at 
intervals, when the exact number of ticks attached in the ears could 
be determined. Apparently they were not thus influenced in any way. 
It seems quite probable that normally the nymphs leave the host at 
night while the latter is at a resting place, in the corral or stable. 
The fact that they crawl up several feet from the ground and secrete 
themselves in cracks and crevices of the boards and timbers near the 
mangers, in the bark of trees, etc., was first observed by Mitchell, 
as reported by Hunter and Hooker (1907). Hooker has noticed 
21448°—Bull. 106—12——5 
