IOO 
Psyche 
[June 
Ootheca carried externally 
during embryogenesis 
[ blattella spp .] 
Ootheca retracted into uterus 
[blaberidae] 
Ootheca retained longer in vestibulum 
ADVANCED ROTATION 
Ootheca dropped shortly after its formation 
[BLATTELLINAE ; ECTOBIINAE; NYCTI BORI N A E] 
NO ROTATION 
Oothecal flange absent; 
[plectopterinae] 
NO ROTATION 
PRIMITIVE ROTATION 
Oothecal flange reduced; 
anterior eggs inside vestibulum 
[plectopterinae] 
Oothecal flange reduced in length; 
anterior eggs outside vestibulum 
[ ARENIVAGA (A.) SPP.; THEREA PETIVERIANA ] 
NO ROTATION 
Ootheca dropped; ootheca with a long flange; 
anterior eggs of ootheca outside vestibulum 
[ ARENIVAGA (PJ CERVERAE ; POLYPHAGA AEGYPTIACA] 
Figure 25. Possible pathways showing how rotation of the ootheca in the 
Blaberoidea and subsequent retraction of the egg case into a uterus could 
have evolved from a polyphagid-like ancestor. 
female’s paraprocts. The rotation exhibited by the Blattellidae 
(Blattellinae, Ectobiinae, and Nyctiborinae) and all of the Blaberidae 
is more highly evolved or advanced because once rotated the anterior 
eggs in the ootheca are in close contact with the tissues in the vesti- 
bulum. This contact was essential for the evolution of ovoviviparity 
