156 
A nest of one of the mason spiders from St. Thomas was 
exhibited by Mr. Sidebotham. Its form was that of an 
irregular tube, composed of clay and bits of stone, rather 
more than 3 inches long and 1 J inch in diameter ; this is 
lined with line silk. The cover is formed of similar clay 
and bits of stone, and has a very beautiful and durable 
hinge of silk fibres. When this nest is built in a hollow on 
the ground and the lid closed it would be next to impossible 
to detect it, and the lid fits so beautifully that no rain can 
penetrate, nor could an enemy without great difficulty open 
the lid from the outside. 
Mr. Sidebotham also brought under the attention of the 
Section a specimen of rosewood from Brazil, showing the 
curious chambers made by one of the carpenter bees. These 
are on a much larger scale and more highly finished than 
those made by our English species. 
Mr. Dancer exhibited an emperor moth, which had been 
found alive, by Mr. W. Mellor, of the Ardwick Lime Works, 
in his house, on the 17th February last. 
“ On the Markings on the Pleurosigma Angulatum and 
on the Lepisma Saccharina,” by J. B. Dancer, F.R.A.S. 
The Author stated that, whilst engaged in testing an 
object glass on some injured valves of the Pleurosigma 
Angulatum, he noticed a set of faint transverse lines on those 
portions of a valve from which the ordinary diagonal 
markings had been removed by abrasion. These transverse 
lines occupied the same positions on the valves as the ordi- 
nary ones, which are visible in perfect valves when oblique 
illumination is thrown in the direction of the length of the 
valve. The covering glass of the slide had been cracked by 
rough usage, causing the partial destruction of the diatoms. 
At first it appeared probable that these were spurious lines, 
caused by moisture, which might have gained access to the 
valves through the crack in the covering glass (such as had 
been noticed by Mr. Hunt, of Birmingham, and described by 
him in the “ Quarterly Journal of Microscopical Science/' 
