segment is longest, and wider than the thorax. The 3rd is shorter and 

 wider, while the 4th and 5th are nearly equal in width and considerably 

 shorter. From this point the segments narrow rapidly and shorten some- 

 what. The ventral surface at first view presents only six segments: the 

 basal ring is hidden as above stated, by the thorax, while the second 

 covers the two following rings, leaving only a narrow rim of the 4th seg- 

 •ment exposed. The other segments present nothing remarkable, narrow- 

 ing toward the tip; the last emarginate. The dorsal surface overlaps 

 somewhat, and forms a beaded margin, more or less visible in various 

 specimens and not marked in the Q . The figure (2) will show the un- 

 derside better than I can describe it. 



Taking a specimen that had been softened, I lifted the abdomen 

 from the tip, and found that it bent readily, separating along the posterior 

 edge of the second dorsal segment and presenting an appearance from 

 the side as shown at figure 3, except that the silky substance was not 

 shown. Above the large plate is a cavity extending upward half the 

 diameter of the whole segment and filled with a pure white cottony sub- 

 stance, consisting of very fine threads cut to exactly the same length, and 

 compressed into the space as closely as it was possible to pack it. Tak- 

 ing it out carefully the pad measured nearly 2 mm. in width by 0.5 mm. 

 in thickness; left to dry a few minutes a slight puff separated the mass, 

 so that, sticking together as a ball, it had expanded to fully 7 mm. in 

 diameter. In the fourth segment was found a similiar cavity with a 

 somewhat smaller pad of this fine silky or cottony substance, and added 

 to the other, a ball fully 10 mm. in diameter was formed, light as air, 

 and fine as the finest floss silk. A section of the abdomen of a specimen 

 barely softened, presented the appearance shown in figure 6. 



In the 2nd segment the cavity opens and is exposed by the simple 

 lifting of the abdomen or dropping the covering plate. The third seg- 

 ment is reduced ventrally to a narrow ring, lined inside with a fine elastic 

 membrane to which the second pad is attached, and this rests in the ven- 

 tral half of the fourth segment which is empty, but otherwise noimal, 

 except that it is not united to the 3rd at its anterior edge. By flexion of 

 the abdomen the distance between the edges of the 3rd and 4th segments 

 is widened and the pad, unattached inferiorly, is exposed. Fig. 3 shows 

 the appearance of the cavities in profile, while fig. 6 represents a section 

 of the abdomen, the fine lines indicating the pad. 



The cavities extend upward to the center of the seghients, where 

 they are separated by a thin chitinous wall; below this, and lining the 

 cavities, is a thin elastic membrane, forming a complete sac. On this 

 the superior or attached portions of the pad rest. 



The upper portion of segments 2 and 3 are empty — i.e. all the or- 



