OF WASHINGTON. 43 
The jar in which the animal was kept was solidly packed with sand to 
the depth of about ten inches. Shortly after the specimen was put in and 
had surveyed its habitation it went to work to dig for itself a gradually 
sloping channel, the deepest portion of which, after being finished, was 
about five cm. below the surface. The transverse section of the burrow is 
in accordance with the general shape of the animal, i. e., transversely oval, 
and not much higher or wider than is necessary to allow the animal to 
move freely forward or backward in it. The mode of operation when dig- 
ging is, as far as remembered, as follows : It appears to select a place where 
there is already somewhat of a depression in the sand, when it commences 
to scrape with one or the other of the powerful palpi a quantity of sand into 
a small heap in front of it. It then grasps the heap, when of sufficient size, 
between both palpi, and, moving backward for some distance from the bur- 
row, turns around and deposits its load, patting and smoothing it some- 
what with one or the other of the palpi. It then rests for a moment, with 
only the antennae playing, as if in thought, and, turning around, retraces 
its way to the opening, always using its long and slender antennae cau- 
tiously to discover its path. When reaching the burrow it goes through 
the same performance as before. The "antennae" are laid backwards during 
the digging, so as not to be in the way. The channel, when done, had 
reached a length of about 75 or 100 mm., but it took several days before it 
was completed, as the animal often either rested for several hours motion- 
less in its burrow or went outside on a hunting expedition. In this case 
the animal was provided with roaches, and its modus operandi was as fol- 
lows : It moved very slowly and cautiously about, with its formidable palpi 
outstretched and opened, whilst the antennae were in constant and quite 
active motion, feeling and touching all objects about it and on all sides, 
to discover some unlucky insect in its way, which it might grasp. When 
near a roach it either stopped at once or moved so slowly as to appear 
almost motionless. The roaches in the jar were evidently much alarmed 
by this rather formidable-looking creature, and ran about in great haste, 
and, if happening to be on the sand, kept away from the Thelyphonus as 
far as possible, generally running up the side of the jar. The larger and, 
therefore, heavier roaches had to keep, however, more or less on the sand, 
and, in their haste to escape this enemy, often ran right between its arms, 
though they generally escaped, by losing a leg or antenna on account of 
the too slow movements of their foe. Sometimes a roach sat quite close 
in front of the Thelyphonus, but with its antennae constantly playing and 
evidently on the alert to avoid a sudden attack. 
The Thelyphonus meanwhi e moves his antennae quite actively though 
very cautiously, stretching now one as far as possible and then the other, 
tapping the roach gently on one side or the other to induce the poor vic- 
tim to move forward. In this endeavor, after many failures, it gradually 
succeeds, and if a roach at last happens, through much coaxing, to get 
between the opened shears in a favorable position, it is suddenly grasped 
with one or both and brought close to the powerful jaws, where it is soon 
