26 Mr. W. King on certain Genera 



line; the elytra more or less powdered with a waxy secretion; the 

 wing white, somewhat hyaline ; head, thorax, body and femora 

 very pale yellow ; the antennee and tibiae blackish ; large tuft of 

 white waxy sponge-like matter at the end of body. 



Expanse of elytra about 1 inch and 4 lines. Brit. Mus. 



Hab. India (Silhet). In some specimens the red mark on the 

 elytra is nearly obsolete, and the transverse black line is quite 

 obsolete anteriorly. 



Pceciloptera (Flatida) tricolor, White. Elytra pale green ; an- 

 terior margin, especially at the base, reddish, the colour gra- 

 dually verging into green ; a few white powdery dots on the basal 

 half, the under side washed with white. Wing white, somewhat 

 powdered, the veins, especially at the base, greenish. Body and 

 legs pale green. 



Expanse of elytra about 1 inch 11 lines. 



Hab. India (Silhet). 



The front edge of wings near the base has a prominent angle, 

 followed by a sinuation. 



June 1S46. 



V. — Remarks on certain Genera belonging to the Class Pallio- 

 branchiata. By William King, Curator of the Museum of 

 the Natural History Society of Northumberland, Durham and 

 Newcastle-upon-Tyne. 



The greatest discordancy of opinion has for some time prevailed 

 with regard to the nomenclature and value of certain generic 

 groups of the Palliobranchiate or Brachiopodous mollusks. A 

 few years since, many palajontologists united such shells as Lep- 

 tcena rugosa and Productus Martini in one group, to which they 

 gave the latter generic name : J. De C. Sowerby * and Professor 

 Phillips t recognise the same association ; but they discard the 

 term Productus and adopt that of Leptaena : M. Bronn in the 

 ' Lethrea Geognostica ' agrees to the same union, but he rejects 

 both names, and uses that of Strophomena. M. de Verneuil 

 groups Terebratula sacculus, Spirifer ambiguus and Atrypa reti- 

 cularis in one genus — Terebratula% ; J. De C. Sowerby would be 

 disposed to make two genera of them ; while Professor Phillips 

 would have little hesitation in separating them into three. Bronn 

 unites Orthis testudinaria and Spirifer speciosus under the genus 

 Trigonotreta. Conrad and other American writers reject the ge- 

 neric name, which on this side of the Atlantic is applied to such 

 shells as Leptama rugosa and L. euglypha, and adopt for the 

 same that of Strophomena. And Mr. M'Coy has been led to im- 



* Silurian System, &c. 

 % Russia in Europe. 



