6G8 DESCRIPTION OF PLATE, 28. 



Fig. I s s s s s s, the six sutures in the walls, separating the six com- 

 partments, of which — 



a is the basal margin of the rostrum, 



c c that of the lateral compartments, 



D d that of the carino-lateral compartments, and 



E that of the carina. 



r, r, rays or spokes of membrane, prolonged from the circum- 

 ferential slip, and running under the trebly folded wall of 

 each compartment, but here cut off; a similar ray should 

 run under each line of suture (s). These rays, at their 

 extremities, expand transversely; and the shape and length 

 of the rays may be judged of from the basal outline of the 

 folded walls given in PI. 16, fig. 5. 



The two cement-ducts, proceeding from each cement-gland, 

 debouch opposite the middle folds of the lateral (c c) and 

 carino-lateral (d d) compartments. The layers of cement 

 have been removed, n.b. There is one considerable error 

 in this figure, the two main trunks, connecting the cement- 

 glands, and meeting at the centre, have been represented as 

 forming a straight line, but in fact they form a very open 

 angle, as is correctly shown in fig. 1 c. 

 Fig. 1 b, Diagram, representing a vertical section through a portion of 

 the basal and parietal membranes, with the thickness of 

 the membrane enormously exaggerated. 



z z z, layers of cement, which, if the section had been made in 

 the line of the cement-ducts, would have been seen pro- 

 ceeding out of these ducts, as is represented at (f), where 

 the section is supposed to have taken the above course. 



c' c', the slips of basal membrane. 



by the circumferential slip ; beneath this the coarsely dotted 

 layer represents the cement, lately excreted, and before it 

 has acquired its proper transparent structureless character, 

 elsewhere represented by fine dots. 



p, membrane externally coating the walls of the shell. 



t, cement-ducts opening beneath the basal membrane. 

 Fig. 1 c, The central portion of fig. 1 a, considerably magnified. 



c' c', slips of the basal membrane ; but the shell, when these 

 were formed, was so young that the walls had not acquired 

 their folded structure; in the centre the prehensile antennae 

 of the pupa may be obscurely seen. 



f 9 the main cement-trunk, connecting the cement-glands. 



h, a cement-gland, from which two cement-ducts proceed. 



a a, cement-ducts (cut off), leading to opposite the middle fold 

 of the carino-lateral compartment. 



b by cement-ducts (cut off), leading to opposite the middle fold 

 of the lateral compartment. 



a' V ', a pair of cement-ducts, with their orifices opening on the 

 under side of one of the slips of basal membrane (c'), at a 

 point which once was opposite the middle of the carino- 

 lateral and lateral compartments. The orifices of the other 

 ducts, towards the centre, maybe seen forming straight lines. 



