Gr. H. F. Nuttall 
81 
medium-sized ones. From the 11 large nymphs there emerged as many 
males, from the medium-sized or small nymphs there emerged eight 
females and three males. All the large nymphs therefore gave rise to 
males, thus confirming me in my view. The large gorged (/* nymphs 
measure 3'7-4'4 mm. in length, the small gorged $ nymphs measure 
3’0-3‘6 mm. in length when alive. The majority of the nymphs 
measure 4 mm. or over, the majority of $ nymphs do not exceed 3'2 mm. 
in length. 
The size of adult I. putus. 
In Tides, Part II., the length of the f is given as 3'7 mm. and that 
of the $ as 3'3 mm., the measurements having been made upon a few 
specimens preserved in alcohol. From the large number which have 
since passed through my hands I am now able to give measurements 
which show that there is a certain variation in size. Five of each sex 
were picked out from about 60 of Lot 1307 as showing obvious 
variations. The dimensions given do not include the capitulum. 
5 S measured 5 ? measured 
Length 
Width 
Length 
Width 
Scutum length 
3'5 mm. 
2-5 mm. 
3-0 mm. 
2-0 mm. 
1'2 mm. 
3-5 
2-3 
2-6 
1-8 
1'5 
3-7 
2-5 
2-.5 
1-6 
1-2 
3-3 
2-6 
3-1 
2-1 
l-o 
3-5 
2-7 
3-0 
2-0 
1-2 
The average 
t? measures 
The average 
j measures 
3-0 X 2-0 mm. 
3-5 X 2-5 mm. Scutum length 1-.3 mm. 
Copulation. 
The process of copulation has been repeatedly observed by me 
both under natural conditions and in the laboratory. At Worm’s 
Head the males were found copulating with gorged females only, but 
as soon as unfed females were brought together with males they 
copulated. The process is identical with that observed in other Ixodes, the 
male introducing spermatophores into the vulva of the female by means 
of his mouth-parts. In one instance the sexes were separated whilst 
in coitu and the bulb of the flask-shaped spermatophore was seen 
protruding from the vulva. By gentle traction the spermatophore neck 
within the vulva was withdrawn without injury. It measured as 
follows: total length IT mm. of which a little over 0'3 mm. goes to the 
bulb, the neck measured just under OT mm. in width, the bulb 0'3 mm. 
Parasitology vi 
6 
