142 The Naturalist in La Plata, 
blade of grass has its colony ; clusters of hundreds 
adhere to the twigs ; myriads are found in the bush 
clumps. Lean and fiat when growing to the leaves, 
the tick catches man or beast brushing by, fattens 
rapidly, and, at the end of a week’s good living, 
drops off, 'plena cruorisT When on trees, Belt says, 
they instinctively place themselves on the extreme 
tips of leaves and shoots, with their hind legs stretch- 
ing out, each foot armed with two hooks or claws, 
with which to lay hold of any animal brushing by. 
During this wretched, incom- 
t plete existence (from wdiich, in 
most cases, it is never destined 
to emerge), its greatest length 
is about one-fourth of an inch ; 
but where it fastens itself to an 
a blood diet. animal the abdomen increases to 
a globe as big as a medium-sized 
Barcelona nut. Being silvery-grey or white in 
colour, it becomes, when thus distended, very con- 
spicuous on any dark surface. I have frequently 
seen black, smooth-haired dogs with their coats 
turned into a perfect garden of these white spider- 
flowers or mushrooms. The white globe is leathery, 
and nothing can injure it ; and the poor beast 
cannot rub, bite, or scratch it off, as it is anchored 
to his flesh by eight sets of hooks and a triangle 
of teeth. 
The ticks inhabiting regions rich in bird and 
insect life, but with few mammals, are in the same 
condition as mosquitoes, as far as the supply of 
blood goes ; and, like the mosquitoes, they are com- 
pelled and able to exist without the nourishment 
