510 Mr. R. She] ford's Studies oj the Blattidx. 



his specimens and found that it contained a perfect egg- 

 cluster of crescentic form, the eggs to tlie number of forty- 

 four and in different stages of development being arranged 

 in a double row. The egg-mass was contained in a thin- 

 walled prolongation of the genital pouch, which may be 

 termed tlie brood sac. Whilst in most cockroaches the 

 egg-capsule is a horny structure, in Panchlora viridis it is 

 a tine membranous sheath enclosing only the basal half 

 of the egg-mass. The colleterial glands have always been 

 regarded as secreting the substance of the horny ootheca 

 of Blattidw, and Riley assumed that they are absent or 

 much reduced in Panchlora viridis but did not test the 

 "truth of his assumption by dissection. From another 

 specimen examined by Riley young larva3 and nearly 

 mature embryoes had been extruded. 



Holmgren in a paper on viviparity amongst insects 

 in general (Zool. Jahrb. Syst. xix, p 484,) records vivi- 

 parity for three more genera of Blattidai, viz. Eustegasta 

 niicans, Sss. and Zhnt., Oxyhaloa saussurei, Borg, and an 

 undetermined species of Blahcra. In the latter species 

 the developing eggs are contained in a horny and sculp- 

 tured capsule which lies in a thin-walled brood-sac and is 

 apparently retained there till the eggs are mature or 

 nearly so. In Eustegasta micans the ootheca splits open 

 whilst still in the brood-sac, and the young larvae emerge 

 two by two from the mother. Holmgren divides Blattidie 

 into three sections according to their method of repro- 

 duction, as follows : — 



1. Oviparous species, which carry the ootheca for some 

 days protruding from the tip of the abdomen. 



Ex. Periplancta. 



2. Viviparous species, the ootheca retained within a 

 brood-sac. 



Ex. Eustegasta, Oxyhaloa, Blahera, 



3. Viviparous species, the ootheca practically absent. 

 Ex. Pa7ichlora. 



To this last section and possibly to the second I am 

 able to add more examples. 



My own attention was specially drawn to this 

 phenomenon of viviparity amongst Blattidx in rather 

 an interestino; manner. Whilst arranging the South 



