512 Mr. R. Shelford on 



of the ootheca, which here presents a double series of 

 imbricating scales ; these scales are in reality the free ends 

 of the lamellae which form the walls of the esff-cells and 

 between them lie the passages to the interior of the egg- 

 cells. The young larvae, when ready to emerge, have 

 merely to push their way along the " canali di uscita," as 

 Giardina terms them, in order to gain access to the outer 

 world. This is a very bald description of an extremely 

 complicated structure, but it suffices for my present purpose, 

 and readers anxious for further details must consult 

 Oiardina's two memoirs. The nests of species of Amcles 

 are described by the same authority ; they chiefly differ 

 from that of Mantis o'eligiosa by the presence of a grooved 

 ridge apparently very like that in the East African 

 oothecae here described ; at the bottom of the ridge occurs 

 the double row of the openings of the " canali di uscita." 

 The ridge, in fact, is strictly homologous with the double 

 row of imbricating scales in the nest of Mantis and is 

 formed by the free ends of the lamellae composing the 

 walls of the egg-cells. I will return to this point later. 



The ootheca of Gongylus gongylodes (sub-fam. Umpusinae) 

 has been described in some detail by Captain C. E. 

 Williams in the Transactions of this Society for 1904, 

 pp. 129-131, and I need not allude further to this excel- 

 lent piece of work beyond remarking that the egg-cells 

 are not protected by a surrounding spongy layer of empty 

 cells but by a layer of hardened foam only |- in. thick ; the 

 young larva " softens the end of the cell in which it lies, 

 and this falls outwards as a small disc hanging by a silk 

 thread," and the larva is now free to walk out of its 

 prison. The ootheca of Hymcno^nts Incornis (sub-fam. 

 HaTj)ctginae) is very like that of Gongylus and the emerg- 

 ence of the larvae is effected in the same manner. 



Turning now to the Blattidae, which are more nearly 

 related to the Mantidae than is any other family of the 

 Orthoptera,* we find that the ootheca of a species such as 

 Blatta oricntalis is a chitinous capsule in which the eggs 

 are tightly packed ; when the larvae are ready to emerge 

 either by their movements or perhaps by the action of a 

 cephalic ampulla (cf Mile. Pavlova, Zool. Anz., 1895, p. 7) 



* Handlirscli (Die fossilen Insekten, p. 1290) regards the Blattidae 

 and the Mantidae as orders of the sub-class Blattaeformia, and the 

 Acridiidae + Locustidae + Gryllidae, the Phasmidae and the Der- 

 maptera as orders of the sub-class Orthopteroidea. 



