ON CRUSTACEA. 
291 
The third sort of land crustaceum of which Rochefort speaks, 
is that which lie designates under the name of pieties, and 
which appears to be the violet-crab of Labat and other travel- 
lers. Those animals, intermediate in size between the pre- 
ceding two, are remarkable for the beauty and agreeable mix- 
ture of their colours. Some are of a violet, variegated with 
white ; others of a fine yellow, varied with purple or greenish 
lines ; others have a tan-coloured ground, striped with red, 
yellow, and green. 
They gnaw, in open day, under the trees to find their food, 
and are usually met with in numerous troops in the morning 
and evening after the rains. The hollow of some rotten tree, 
the cavities which are under its roots, or the cleft of a rock, 
usually constitute the asylum where they take refuge, and 
withdraw themselves from the view of their enemies. Mauge 
informed M. Latreille that they climb sometimes on trees, to 
take the young birds in their nests. 
Rochefort states that they repair every year, towards the 
month of Maj^ or June, in the rainy season, to the sea shore 
to lay their eggs there, and perpetuate their race, travelling 
from the mountains, in which they make their habitual 
dwelling, in such numbers that the roads and woods are en- 
tirely covered by them. They possess the instinct of direct- 
ing their course towards the parts, which, by their descents 
or natural declivities, facilitate their journey, and permit their 
more convenient approach to the sea shore, which constitutes 
the limit of their migrations. This migration has been assimi- 
lated to an army marching in order of battle, with unbroken 
ranks and undeviating line. They scale the houses and rocks, 
and surmount every obstacle which they may encounter in their 
path ; the gardens situated on their passage often suffer greatly 
from their depredations. Sometimes they even penetrate into 
houses, especially in the night, and disturb the inmates by 
the noise they make. The males being well fed, and the 
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