aoe 
1900-1901.| A Field Naturalists Holiday. 137 
the best photographs of wild animals I ever saw—by far the 
best. They were taken by a rich American, Mr Shiras. He 
began by studying the habits of the animal he wished to 
photograph. He paid particular attention to its nocturnal 
habits—where it went to drink or to lick salt. He placed 
several cameras in position, and made them work automati- 
cally: he placed wires in the grass, which, being pulled, 
discharged a spark of electricity, and so fired in some way 
magnesium powder. One would think he must have spoiled 
a vast number of plates: still, those he exhibited were master- 
pieces. 
We go on now to the Champ de Mars—the largest of all 
the parts of the Exhibition. We neglect the piles of cloth 
(the textile industries), the gallery after gallery of bottles of 
chemicals and apparatus used in chemical industries. We 
go straight to the Science and Art and Education section. 
I want to tell you of only two or three things. One exhibit 
interested me much. It was six ants’ nests, with their com- 
mensals and parasites all alive and displaying the utmost 
activity. The nests were made of red terra-cotta—very like 
what better-class flower-pots are made of: they were in the 
shape of square tiles about an inch thick and about a foot 
on each side. They had deep grooves in them, made, when 
the clay was moist, by an inch gouge. The grooves made a 
seroll figure. One side of the tile was kept moist—a moist 
chamber—and the whole was covered by a plate of glass, 
and that again by a thick curtain. When the curtain was 
drawn aside, there were the insects at work. I do not know 
what they were fed on. The exhibitor, M. Charles Janet, 
has written a pamphlet on them, which I have just got. 
Beside each nest there was a long description of the insects it 
contained. The reading of this was not easy, because there 
were generally several people waiting their turn to have a 
look. There is a nest of red ants (Myrmica rubra); in it 
there are a commensal and a parasite: the one—Platyarthus 
Hoffmannseggi—is a little land crustacean. It is white, and it 
is blind. It seems to find its way about by its sense of smell. 
An organ of smell is said to be placed in the antenne. It 
eats animal and vegetable matter, which it finds in the 
galleries, and it moves about little The other is a parasite 
