Royal Physical Society. 33 



they belong to the lid itself. On removing the lid we see a 

 beautiful porcelain chamber of a pale French white colour, bear- 

 ing a close resemblance to the texture of a hen's egg, but it is 

 not calcareous, and has more the appearance of enamel. On 

 holding this shell between us and the light, we see light spaces 

 where the holes in the cortical outer covering terminate, and in 

 the centre of each there is a darker space, as if it were a pore ; 

 but this conjecture I have not been able to verify. The sub- 

 stance composing the outer cortical covering is very curious. 

 It is very thick. Looked at with the naked eye it seems of a 

 spongy, reticulated, fibrous structure. But under the micro- 

 scope we see that it is composed of cells, generally arranged in 

 rows radiating outwards ; some irregularly shaped, but most 

 of them with a greater or less tendency to a pentagonal or 

 hexagonal shape. In fact, in some parts both the substance 

 and structure bear a most striking resemblance to a piece of 

 honeycomb. 



It seems not difficult to conjecture the purpose which the 

 cellular texture of this outer covering serves. If it had been 

 of a firm close substance, the embryo insect could not have re- 

 ceived the amount of air and moisture necessary for its exis- 

 tence, and which, from what I shall presently detail, are more 

 than usually necessary in this family of insects. 



Having received from Mrs Blackwood one or two unhatched 

 eggs, and the shells of others which had been hatched, I was 

 enabled to make an examination of the interior. On breaking 

 into the egg which had been hatched I found two pellucid mem- 

 branes, one within the other, the outer one doubtless cor- 

 responding to the chorion. On breaking open an addle egg, I 

 found first a pellucid membrane (the chorion), and within it a 

 clear carmine-coloured capsule, flask-shaped at bottom, but 

 flat at the top. 



This capsule might at first be taken for the dried-up 

 yolk of the egg ; but if our readers will give me their for- 

 bearance, I trust to satisfy them that it is something very 

 different. In order to do so, I must take them a little way back 

 into the elements of entomology. They are doubtless aware 

 that the Orthoptera (to which order of insects the Phyllium 

 belongs) are characterized by what is called a semi-complete 



