CYCLOTACEA. 263 



* 19. Pterocyclus (Rhiostoma) housei, Haines. 



2 Siam; ex c. Mr. Cuming. 



20. Pterocyclus (Ehiostoma) hainesi, Pfeiffer. 



1 Siam ; coll. Baron P. von Kiclitliof en. 



Sub-GenuB OPISTHOPOSUS, Bensou. 



—, 21. Pterocyclus (Opisthoporus) birostris, Pfeiffer. 



1 Borneo j ex c. Mr. Cuming. 



- 22. Pterocyclus (Opisthoporus) euryomphalus, Pfr. 



1 Borneo ; ex c. G. Nevill, Esq. 



- 23. Pterocyclus (Opisthoporus) biciliatus, Mss. 



2 Borneo ; ex c. Mr. Cuming. 



-, 24. Pterocyclus (Opisthoporus) solutus, Stoliczka. 



8 Penang (type); coU. Dr. F, Stoliczka. 



8 Buket Poudong ; coll. Dr. Edmund Townsend. 



- 25. Pterocyclus (Opisthoporus) penangensis, Stol. 



14 Penang (type) ; coll. Dr. P. Stoliczka. 



14 Buket Pondong ; coll. Dr. Edmund Townsend. 



Sub-Genus SPIRACULUM, Pearson (type P. Uspidus, 

 Pearson). 



- 1 26. Pterocyclus (Spiraculum) hispidus, Pearson. 



3 North- East Frontier, Bengal (type) ; ex As. Soc, Bengal. 

 16 Teria GMt; coll. Major H. H. Godwin- Austen. 



Tar. minor (? distinct species). 



2 North-East Frontier ; ex As. Soc, Bengal. 



9 Teria GMt ; coll. Major H. H. Godwin-Austen ; two of these Dr. F. 



Stoliczka labelled $ and one 2 (slightly larger). 



* 27. Pterocyclus (Spiraculum) masters!, Hani. & 



Theob. 



15 Upper Assam (typical) ; coll. Mr. Masters. 



Tar. simplex (? distinct species). 



Of much simpler characters than the typical form. The last 

 whorl only a little detached ; the sutural tube not bent back ; 



