260 



Dr. Malcolm Burr on the Opisthomeres 



In Echinosoma afrum, Beauv., I can see only two plates, 

 which are strongly transverse : a faint suture perhaps 

 indicates the fusion of the metapygidium with the 



Fig. 4. — Echinosoma afrum, Beauv., i . 



pygidium ; the telson appears only represented by a faint 

 membrane. 



In the AUostethinae, Zacher says that all three plates are 

 equally big, with which I cannot agree at all. In all my 



Fig. 5. — AUostethus indicum. Hag., <5 . 



specimens of this group, the pygidium is far bigger than 

 the rest of the opisthomeres, being of the same shape as in 

 Pyragra. In the female and nymph of All. indicinn. the 

 metapygidium is constricted about the middle, then strongly 



