0)1 some new or imperfectlij-hnowa Stromatoporoids. 225 



Terias messalina group. 



T. messalina, Fabr. ; T. gnathene, Boisd. 



Though much resembling the preceding group on the upper 

 surface, I believe tliat these are merely white species of the 

 T. dina group. 



Terias herla group. 



T. hetheseha, Jans. ; T. herla, M'Leay ; T. vagans, Wall. ; 

 T. Jcegeri, Menetr. ; T. loeta, Boisd. ; T. subfervens, Butl. 



This group is perfectly connected through T. hetheseha with 

 the jT. wi'se group [T. regularis) , and therefore in arranging 

 the genus 1 have placed it between T. regidaris and T. neda ; 

 yet the acute primaries of some of the species, and the unusual 

 style of pattern and coloration on the under surface of their 

 Avings, suggests that they should rightly terminate the genus. 

 It is, of course, impossible to arrange every large genus in a 

 linear series, for, at certain points, two divergent series will 

 occasionally branch out, as appears to have occurred in the 

 present instance. 



Terias Jcegeri, Menetrids. 



This species has of late years been incorrectly identified 

 with a Japanese butterfly, from which it is perfectly distinct : 

 it was described from a N.W. Indian specimen, and is with- 

 out doubt the pale representative of T. Iceta ; but whether it is 

 distinct, or is a seasonal form or mere dimorphic variety of 

 T. Iceta, can only be proved by repeated observation on some 

 spot where it abounds or by careful breeding. The point 

 being doubtful, I hesitate to separate the Japanese form from 

 T. subfervens of S. Corea : it differs from it normally as T. 

 Jcegeri does from T. Iceta ; but individuals in a large series 

 obtained in Japan show a tendency towards the iiery under- 

 surface colouring of T. subfervens. 



The species described under the names T. reticulata and T. 

 atinas are tailless species of Sjjhcenogona, their neuration being 

 quite different from that of Terias. 



XX. — On some new or imperfectly -know a Species of Stroma- 

 toporoids. By H. Alleyne Nicholson, M.D., D.Sc, 

 Regius Professor of Natural History in the University of 

 Aberdeen. — Part I. 



[Plates Vl.-Vril.] 



Having been for some time engaged in the preparation of a 

 Monograph of the British Stromatoporoids for the Palajonto- 



