NESTS OF PSEULOSCORPIONES. 105 
up the inside and down the outside each time it went out, and 
up the outside and down the inside each time it returned; and 
further, there was increasing difficulty in fixing the fragments 
against gravitation as the structure converged towards the top of 
the roof. The animal was watched for five and a half hours, 
during which it worked untiringly and with care, with brisk and 
eager movements and without once resting. Its activity was 
remarkable. When I left it at 11.30 p.m. only a small aperture 
at the top of the roof remained to be filled in, and thus the 
framework of the nest was almost complete. It must be explained 
that the silk dried rapidly, the structure being firm from the first, 
so that it was little if at all damaged by the continued scrambling 
in and out of the animal. At the same time a certain elasticity 
was evident, and thus during the final stages of this part of the 
work—not seen in the present case—the animal would not be 
greatly obstructed in forcing its way in and out of the small 
decreasing aperture. Next day, at 7.30 a.m., the framework was 
complete, the aperture having been filled in, and the builder was 
thus entirely enclosed. The creature was still busy, however, 
within the nest. One could see that the palp-fingers were being 
applied from place to place, and the structure was temporarily 
raised or pushed out first in one part and then in another. The 
animal was evidently spinning, and at the same time re-adjusting 
the materials to some extent; and it even detached and threw out 
certain fragments, dried remains of prey ete., which had originally 
been built in. 
The structure thus made consisted of a vast number of irregular, 
mostly small, fragments of wood and cork fastened together by 
silk attached to their inner surfaces and extending from one to 
the other; and the arrangement was such that the interior had 
a regular approximately even surface. The silken attachments— 
seen by looking down between the fragments—had the character 
of an open irregularly joined-up meshwork, of which the threads 
were of varying thickness, most of them relatively stout. This 
meshwork ought perhaps to be regarded as the essential frame of 
the structure ; the use of fragments is probably necessary in nests 
entirely unattached above but otherwise it is not indispensable ; 
for the animal is able, at least in certain positions, to make nests 
ef spinning-work alone. The task of bringing the nest to the 
condition now indicated had entailed much work; but what 
remained to be done was more laborious and occupied a longer 
time. Thisadditional work consisted of long-continued spinning, 
the meshwork, the inner surfaces of the fragments, and in fact 
the whole interior, including the floor, having to be covered with 
silk, until at last every part was lined with the almost paper-like 
tissue already described. 
The making of nests such as that above considered, though 
showing well the manipulation of the extraneous materials, 
offered but moderate facilities for observing the spinning. This 
was better seen in nests made in the spaces between the strips 
