ON TRACI1EAN ARACHNIDA. 
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feet goes on increasing, beginning from the second pair. 
They are shorter and thicker in clielifer (proper) than in 
obisium. 
These arachnida are very small. The most common species, 
the scorpion araignee of Geoffroy, is found in humid places, 
under stones and garden flower-pots, in the unfrequented parts of 
houses, in dust, old books, and herbals. It lives on those little 
insects called psocus pulsalorius by Fabricius, on small acari, 
and it even attaches itself to flies. Goetze assures us that he has 
fed it with small aphides. Linnaeus tells us that it sometimes 
introduces itself into the skin, and there produces a painful 
swelling of the size of a pea. He even relates, on the faith of 
Dr. Bergius, that a peasant, during the night, having had his 
thigh pierced by one of these arachnida, there formed a pus- 
tule, of the size of a nut, which occasioned most frightful 
torment. But these facts require authentication. When this 
arachnid is pursued, or when it meets in its way some object 
that it is desirous to avoid, it walks tolerably fast, both for- 
wards, backwards, and sideways, like the scorpion and the 
crab. Rcesel has seen the female lay small eggs of a greenish 
white, and assemble them one beside the other. But he has 
not told us whether the young took a long time to come forth 
from these eggs. 
The elder Hermann, according to the testimony of his son, 
has seen the same animal carrying its eggs, gathered up in a 
pellet under its belly, after the fashion of many aranei’des. 
He once found one of them enclosed in a silken follicle, 
covered with dust, and attached to a wall by one of its sides. 
It is M. Latreille’s opinion that this cocoon was foreign 
to this animal, and that it merely made it its temporary 
domicile. 
The Pycnogonides appear to M. Savigny to form the 
passage from the Crustacea to the arachnida. The Pycno- 
gona differ from the other genera of the same family, not 
