2 
On Coloration in Ticks 
In A. hebraeum 
Young, unfed, living 
Ditto, dead, dry 
Old, fed, living 
Old, fed, dead, dry 
Ditto in alcohol (old 
or young) 
In A. gemma 
Young, unfed, living 
Ditto, dead, dry 
Ditto in alcohol (old 
or young) 
* 
Colour changes in the Scutum. 
Male 
Greater part of Lateral and marginal Festoons 
pale area pale areas, scapulae where pale 
Pale violet 
Pale yellow to pale 
yellowish green 
Pale green 
Pale green 
Deep violet with 
green or coppery 
sheen at borders 
Ochre 
Pale ochre 
Red 
Red* 
Dark copper 
with green 
sheen 
Pale yellow 
Pale yellow 
Bright yellow 
Bright yellow 
Copper with 
green sheen 
Salmon, fine bor- Yellow 
der of yellow 
Pale yellow 
Pale orange yellow Pale orange 
yellow 
Copper with blue Copper with 
and green sheen blue and 
green sheen 
Pale yellow 
Pale copper 
A few specimens had bleached somewhat after 5 years. 
Female 
Greater part of 
pale area 
Pale yellow 
Dirty yellow 
Pink with violet' 
gold and green 
sheen 
Orange, middle 
violet, posterior 
margin pale 
violet 
Pale yellow 
Copper with gold 
and green sheen 
at borders 
The foregoing table serves to illustrate how very differently the ticks’ 
colours appear according to the conditions in which they are examined. In 
all of the alcoholic specimens the colours are metallic, i.e. when viewed by 
reflected light the coloured parts have the appearance of burnished metal. 
As stated in my previous paper (loc. cit. p. 50), when dried specimens are 
placed in alcohol the colours become metallic, and vice versa. I do not know 
of any ticks that show metallic colours when alive. 
Dermacentor. 
In the species of this genus herein depicted, metallic colours are absent in 
alcoholic specimens, therefore the colour changes observed in living and 
variously preserved examples are not so material as in most of the other 
ornate ticks. In dead specimens, the faint greenish tint seen in the illustration 
of D. venustus may disappear and the darker areas may become blackish in 
D. reticulatus niveus. 
Dermacentor reticulatus niveus Neumann. Plate II, figs. 4 and 5 represent 
(N. 2156) a $ and $ received in May 1913 from Pina, Spain. I have described 
the biology of this tick elsewhere, having raised the progeny of the pair here 
figured (see iii. 1915, Parasitology , vn. 421-425). 
Dermacentor venustus Banks. Plate II, figs. 1 and 2 represent the $ and $ 
of this North American species which is the carrier of Pocky Mountain Fever 
to man. The specimens figured (N. 1731) were received in June 1912 from 
Ottawa, Canada. A description of the biology of this species will be found 
elsewhere (loc. cit. pp. 425-430). 
