G Mr. F. Muir and Dj-. D. Sharp on 



next membrane a little way off. These various facts are 

 seen by examining those cells, at the t-vo ends, that contain 

 no eggs : at these places the cellular structure still exists, 

 though in more irregular fashion than in the area of the 

 egg-containing cells. The outer row of cells on each side 

 is quite different in form and never contains any egg. 

 Though this outer layer (fig. 2, PI. I) appears to consist of 

 closed cells, it is very easy to convince oneself that the 

 apparent cells are not really such, but are merely due to 

 the curling of the membranes where they have a free 

 projection externally. 



A very remarkable feature of the membranes is that at 

 the edges they are often provided with a delicate in- 

 crassation or margin. This adds greatly to their strength, 

 and assists their retention of the shape given to each 

 membrane at the moment of its being added to the edifice. 



Before considering some points of general interest we 

 will give some brief particulars as to other Cassid oothecas 

 discovered by Mr. Muir in Natal near Durban. 



2. As'indomorplia tain. 



This ootheca is mucli smaller than that of A. 

 pnncticosta ; it contains only from 14 to 20 eggs. It is 

 attached to the leaf of the food-plant — Ipomau holosericca 

 — in a very different manner. One membrane only is 

 attached to the leaf, and by its broad face; this membrane 

 is folded at the bottom and the part that is reflexed up- 

 wards is very much curved, so that the rest of the mem- 

 branes repose in it as if it were a cup. The transverse 

 section of this ootheca is composed of onlya single membrane 

 — not of six as in A. pundicosta — and there appear to be 

 only seven or eight membranes in the whole structure. 

 The differentiation between the first and last of these 

 membranes is very remarkable. We have no particulars 

 as to the mode of construction, and have seen so few 

 specimens that we cannot set forth its intimate structure. 



3. Asjndomorj^Jia Conjinis. 



PL II, figs. lU, 11. 



The ootheca (figs. 10, 11) is small, it is attached to the 

 leaf of the food-plant, Ipomau holosericca; the first mem- 

 brane has a wide attachment to the leaf, but is destitute 



