THE ENTOMOLOGIST. 243 



overlaid with other patches more and more extensive, until 

 the whole interior walls are covered ; after which the silk is 

 spun evenly and continuously all round the interior, in 

 successive layers of very dense texture, though thin. Under 

 the microscope, with a power of 220 diameters, these layers 

 are resolved into threads laid across each other, and intertwined 

 in a very irregular manner; some are simple, varying from a 

 seven-thousandth to a two-thousandth of an inch in diameter, 

 and others are compound, several threads in one part separate, 

 being united into one of greater thickness, which cannot then 

 be resolved. No pellets of earth are ever interwoven with the 

 silk to form the outer layers of the walls, though the adhesive 

 nature of the silk when freshly spun causes fragments of earth 

 to remain attached to the surface. The mouth of the tube is 

 commonly dilated a little, so as to form a slightly recurved brim 

 or lip ; and the lid is sometimes a little convex internally, so as 

 to fall more accurately into the mouth and close it. The thick- 

 ening of the hinge by additional layers is, 1 think, accidental 

 only, as out of the many specimens I have examined only 

 one or two had such a structure. In the neatest examples 

 the lid is of equal thickness throughout its extent, agreeing 

 also with the walls for the first few inches of their depth. 



" One of peculiar compactness, now before me, I have slit 

 open longitudinally with a pair of scissors in the manner 

 spoken of above : the thickness of the substance is in no 

 place greater than one-sixteenth of an inch, which is very 

 regularly maintained throughout the lid and upper parts. The 

 appearance at the cut edge closely resembles mill-board so 

 divided; the layers of which it is composed being very 

 numerous and compact, especially towards the interior side, 

 where they can scarcely be distinguished even with a lens. 

 In this specimen there is what I cannot find in any of the 

 others I have examined. A row of minute holes, such as 

 might be made by a very fine needle, are pierced around the 

 free edge of the lid, and a double row of similar holes just 

 within the margin of the lube. There are about fifteen or 

 sixteen punctures in each series, and they penetrate through 

 the whole substance, the light being clearly seen through each 

 hole. Now what is the object of these orifices .'' 1 do not 

 think, as I have somewhere seen suggested, that they are 

 intended to afford a hold for the spider's claws when she 



