the egg -cases and early stages of some Cassididie. 5 



only two eggs are placed in a row by the Insect they form 

 actually four series. 



The special structures of the female Asp. intneticosta* 

 (PI. I, figs. 7, 8.) The external orifice of the cloacal 

 chamber is transversely elongate, and its lips are sur- 

 rounded by short hairs, Wlien the lower lip is forced 

 open two oothecal plates can be seen. A pair of colleterial 

 glands, in addition to a spermatheca, the oviduct, and the 

 intestine open into this chamber. The structure considered 

 to be a spermatheca is a chitinous chamber, with a long 

 slender spiral cliitinous tube connecting it with the base of 

 the oviduct. It is very different from any spermatheca 

 Mr. Muir has observed in other Insects : but according to 

 Stein f this form is probably specially characteristic of Cas- 

 sididce. The two diagrammatic figures, 7 and 8, give an 

 idea of the relations of these parts. 



With the aid of this brief description of the actual mode 

 of proceeding, and a similarly brief review of the structures 

 used, it is possible to understand the nature of the ootheca. 



The shape of a single membrane is very peculiar (PI. I, 

 fig. 4) ; it is narrow where it is attached to the egg, and 

 becomes broader as it gets to its end. The exact shape 

 cannot be perfectly ascertained, as we have failed to isolate 

 them without tearing, after they have been stuck together 

 by the Insect. They are clearly very far from being all 

 alike, but the general shape can be gathered from the 

 diagram fio-. 4, which shows one of them isolated, and from 

 fig. 5, which shows two of them together but isolated from 

 their neighbours. 



The membranes are soft and pliable when extruded from 

 the oothecal cavity, and rapidly become solid, and thus 

 retain the form they are made to assume during the con- 

 struction. The cells are made to a large extent by the 

 eggs pushing apart the membranes in some places, and 

 pushing them together in others, but they are partly due 

 to the shape of the membranes, which are, each one, curvate, 

 and moreover are doubled so that sometimes two concave 

 faces are brought together ; in other cases the outside edge 

 of a membrane projects somewhat, and thus keeps the 



* This account is entirely due to Mr. Muir. The dried specimens 

 at my disposal do not enable me to form any idea as to the rather 

 complex structures involved. — D. S. 



t Stein ; Geschlechts-Organe bei den weiblichen Kiifern, 1847, p. 

 132, PL Vir, tig. xvii. 



