406 Dr. T. A. Chapman on 



some exotic CEketicids with large roomy sacs, it extends 

 all round the pnpa, forming a loose hammock inside the 

 sac, in which it rests. We are concerned however just 

 now with oimccUa. This silk must have a somewhat 

 valvular arrangement as the moth forces her way through 

 it, to protrude the thoracic segments from the sac, and on 

 retiring the silk largely closes together again. One such 

 journey results in great damage to her growth of silky 

 wool, which is entangled in the mouth of the pupa case, 

 amongst this silk and in the open mouth of the sac. 



It occurred to me that the only way to find a specimen 

 with this clothing of wool complete would be to find a 

 specimen still unemerged from the pupa, though thoroughly 

 mature, and to carefully remove the pupa case. 



Tills is not quite so easily done as said ; I succeeded, 

 however, in several instances, with very little damage to 

 the specimens. 



A specimen so obtained, presents six abdominal seg- 

 ments, with rings of white, silvery or silken hairs or wool, 

 encircling thorn more or less completely except dorsally. 



Tlie first abdominal segment is a narrow one and has 

 no clothing. The next six segments, second, third, fourth, 

 fifth, sixtli and seventh, have each a ring of wool clothing 

 the whole segment, with the exception of a narrow break 

 dorsally. The wool arises from the wdiole segment, as we 

 usually understand a segment, but each ring of wool is 

 separated from the next by the naked area formed by the 

 expanded intersegmental membranes. The hairs are a 

 little denser on each side of the ventral line, again above 

 this, and again beneath the spiracles, but hardly enough 

 so to entitle these to be called tufts. The hairs are waved, 

 and though not perfectly white, have a very white silvery 

 silken look against the yellower tint of the insect itself. 



The interior silken net of female sac, when it becomes 

 a cocoon, has several uses. The female pupa does not 

 leave the sac ; but more than this it has to be kept in its 

 place during the several journeys to and fro that the moth 

 makes from it to the mouth of the sac and back, and also 

 during the access of the male. In A. opacclla it accom- 

 plishes this by fitting the front of the pupa case, and also 

 by some of its meshes being caught and entangled on the 

 projections that the appendages, aborted mouth parts, 

 legs, etc. present. It thus acts as a cremaster botli before 

 and after the emergence of the moth, preventing the 



