*204 Bioloffj/ oj Pediculus humanus 
The linen was laid on a glass plate, and the various dyes were applied uniformly 
thereto by means of a feather upon the desired areas within the paraffined 
boundaries. The fabric became saturated with the dye, whilst the paraffin 
set limits to its spread. The surplus dye was absorbed with filter paper and 
the carpet was allowed to dry. 
Experiments. 
Light and Shade. Unfed and fed lice, in lots of 50, placed on a white paper 
carpet and illuminated vertically by a bright light, scattered uniformly on the 
floor of the cell, but after a time they gathered along the cell wall seeking to 
escape. When half of the cell was covered with black cloth, they sought the 
shade, only a few wandering about on the lighted surface. 
White and black carpet. Unfed lice, in lots of 50, were placed on the black 
and white quartered carpet (Fig. IB) being illuminated from above. 80 per 
cent, were counted on the black and 20 per cent, on the white. When the 
apparatus was placed in a room and the light from the sky was reflected down 
vertically by a mirror, 81 per cent, were counted on the black and 19 per cent, 
on the white. The total counts in both series of observations were 491 black 
and 119 white. 
Coloured screen. Unfed and fed lice in lots of 50, placed on a white paper 
carpet and illuminated vertically through the screen, gave the following counts 
after 15-20 minutes exposure: 
Set I. 
Lice unfed 16 hrs 
Set II. 
Lice unfed 22 hrs 
Set III. 
Lice fed 2-3 hrs before 
Colour 
No. counted 
% 
No. counted 
Of 
/ o 
No. counted 
% 
Violet 
104 
52 
33 
22 
82 
41 
Indigo 
33 
16-5 
26 
17-3 
28 
24 
Blue 
17 
8-5 
23 
15-3 
39 
19-5 
Green 
13 
6-5 
14 
9-3 
17 
8-5 
Yellow 
13 
6-5 
21 
14 
7 
3-5 
/ 
Orange 
12 
6 
13 
8-6 
11 
5*5 
Red 
5 
2-5 
20 
13-3 
16 
8 
In white centre 
3 
— 
— 
Totals 
200 
150 
200 
Coloured 
carpet. Two series 
of experiments 
were 
carried out, but thev 
y %/ 
afforded no 
evidence 
that the 
lice were influenced 
by the colours 
on the 
carpet. 
Conclusions. 
The foregoing experiments demonstrate that lice, when illuminated by 
rays of light falling vertically upon them, seek the shade, and a black surface 
in preference to a white one. The experiments were conducted at 17-20° and 
20-23° C. 
When exposed upon white paper beneath a screen with bright spectral 
colours, either after fasting 16 hours (Set I) or 2-3 hours after feeding (Set III), 
the majority (52 per cent, and 41 per cent.) gathered beneath the violet, whilst 
