292 MR. A. G. BUTLER ON A NEW FOSSIL, MOTH. [May 21, 



The elytra, when seen without a lens, have a mottled appearance, 

 and the darker portions or spots are of more or less intensity in the 

 diiferent specimens ; the underside is always very dark. 



Malacosoma olivaceum, Fabr. 

 Corozal. 



Malacosoma encausticum. Germ. 

 Colonia Tovar and San Esteban. 



2. Description of a new Genus of Fossil Motlis belonging to 

 the Geometrid Family Euschemida. By Arthur G. 

 Butler, F.L.S., F.Z.S., Assistant-Keeper, Zoological 

 Department, British Museum (Nat. Hist.). 



[Received May IS, 1889.] 



(Plate XXXI.) 



I have to thank Mr. Robert Etheridge for showing me, and Dr, 

 Henry Woodward for giving me permission to describe, an exceed- 

 ingly interesting Motli from the Eocene Freshwater Limestone of 

 Gurnet Bay, Isle of Wight. ; collected by Mr. E. J. A'Court Smith. 

 This is oneof the insects found in the Tertiary Nodules on the beach. 



In his paper published iu 1879 (Quart. Journ. Geol. Soc. 

 vol. XXXV. pp. 342-3), and entitled " On the Occurrence of Branchi- 

 pus (or Chirocephdlus) in a Fossil State, associated with Eospliceroma 

 and with numerous Insect-remains, in the Eocene Freshwater (Bem- 

 bridge) Limestone of Gurnet Bay, Isle of Wight," Dr. Woodward 

 says : — 



"To Mr. E. J. A'Court Smith is due the credit of the discovery 

 of a thin but very richly fossiliferous baud in this series of deposits 

 at Thorness and Gurnet Bays, near Cowes, which has largly increased 

 the interest of these beds, especially by a very important addition to 

 the known terrestrial forms of life belonging to the Eocene period. 



" The section is as follows : — 



" Oenerdl Section at Thorness and Gurnet Bays. 



Thickness. 



Surface soil. ft. in. 



I. Grey Clays with occasional bones of Emijs or Trionyx 10 



II. Lighter ( Yellow) Clays with broken shells 2 



III. LimncBa Limestone with Planorhis and bones of Emys, also 



hard concretions ( Hard limestone bed) 3 



IV. Variegated fossiliferous Clays 8 



V. Upper Limestone beds with lAmncsa and small oblong Oyster 



{Ostrca sp.'?) 3 



VI. Band of loose shells with Osire® and Sharks' teeth 6 



VIL Blue Clays with Cyre?ja 3 



VIII. Fossil Plant- and Insect-bed 1 



Base of cliff. 



30 6" 



