514 Mr. K. Shelford on Mantid oothecae. 



regards the emergence of the larvae, so that if it is the 

 morphological equivalent of the grooved ridge in Ameles 

 ootheca and of the imbricating scales of Mantis oothecae — 

 and I am by no means convinced that this is the case — it is 

 certainly not the physiological equivalent of those struc- 

 tures. The sequence of events in the construction of the 

 African oothecae can, in the absence of direct observations, 

 only be guessed at. The first part to be formed is evi- 

 dently the attaching ring, then on this is built in a semi- 

 circular sweep the grooved ridge, to Avhich is fixed the 

 septum with the eggs ; the final stage in the process is 

 probably the formation of the thin enveloping wall. Such 

 may or may not be the sequence of events — an hour's 

 observation of the living insect at work can upset the 

 most closely-reasoned theory formed in the museum or 

 laboratory. It is noteworthy that neither in the African 

 nor South American oothecae are the eggs enclosed in 

 separate cells. 



Bilateral symmetry, which is so marked a characteristic 

 of all Mantid oothecae, is clearly distinguishable in the 

 African egg-cases here described, but is scarcely to be dis- 

 tinguished in the South American specimen owing to its 

 spherical shape and to the radiate arrangement of the 

 eggs ; the position of the septum is the only feature that 

 remains to show that this ootheca is derived from a 

 bilaterally symmetrical form, 



A much reduced figure of an ootheca from the Egyptian 

 Sudan, closely resembling those described above from 

 Delagoa Bay, is figured on Plate II of SitzB. Kais. Akad. 

 Wiss. math, naturw. Klasse cxvi, Abt. 1 (1907); it was 

 taken at Gondokoro by Dr. Fr. Werner. There is no 

 mention of it in the text. 



Explanation of Plate XVII. 



[t^ee Explanation faci-ny the Plate.] 



Dec. 31, 1909. 



