G. H. F. Nuttall 
91 
Summary. 
Attempts to raise Ixodes hexagonus upon their natural hosts in 
captivity have hitherto failed. From what we have observed we know 
that the tick requires three hosts upon which to feed, in the larval, 
nymphal and adult stages respectively. There is no evidence that 
the male ever sucks bloodk Oviposition takes place in 8-14 days after 
the female abandons the host in the spring and the process lasts 32 days 
at 9'5° C., the female may survive about a week after oviposition has 
ended. The female may lay 250 to 650 eggs, a comparatively small 
number, the tick being usually found on burrowing animalsk The time 
required for metamorphosis from the egg to the larval stage varied 
between 73 and 102 days and the corresponding pei’iod for the change 
from nymph and adult was 77 days at 13-18'5° C. An unfed female 
survived for 142 days at a temperature of 66° C. when confined in a pill¬ 
box. Unfed larvae survived at least three months. 
IXODES RICINUS. 
In Ticks, Part II. pp. 296-315, besides reporting original observations, 
I summarized what was known regarding the biology of this species. 
The following records give information of a somewhat more exact 
character in respect to several matters: 
Lanae. 
No. of 
Time 
Date when 
the tick remains upon 
Host main- Number of gorged 
tained at ticks collected on 
the ho.st. 
Host 
Lot 
ljut on host 
a temp, of 
successive days 
Remarks 
Calf 
1308 
3. X. 1911 
16° C. 
270 on day! 
30 ,, 6 
Progeny of ticks from Ireland. 
Larvae had fasted 86-93 days 
before being put on calf. 
„ 1308 
Nymiihs. 
10. X. 1911 
16" C. 
3 on day 3 
2 „ ' 4 
12 „ 5 
190 ,, 6-7 
179 ,, 8 
40 „ 9 
45 ,, 10 
Ditto. 
Ram 1.560 
Adults. 
7.III.1912 
6° C. 
4 on day 3 
7 „ 4 
1 „ 6 
Ticks from Tregothnan, Corn¬ 
wall. 
Earn 15fi0 7.iii.l912 6° C. 
1 on day 4 Ditto. 
2 „ 5 
1 „ 7 
^ Regarding the habits of the male see my earlier paper in Parasitology, iv. p. 67. 
