^i] ( M 



by the Thyridia ; for the species allied to the former, — Jfethona 

 themisto, Hiibn., and M. singularis, Staud., — resemble J/. 

 confusa; while in the Thyridias allied to j^sidii, — pallida, 

 Godm. and Salv., ceto, Feld., and cedesia, D. & H., — a compara- 

 tively large section of the pale basal area is visible below 

 the nervure. Thyridia kij)2^odainia, F., presents a condition 

 similar to that of T. psidii. 



There is also a tendency in the Itunas and especially in 

 Eidresis imitatrix, for the median transparent area to be 

 nearly equally divided by the black and prominent vein which 

 traverses it. This tendency is less marked in the Thyridia, 

 and still less in the 2Iethona ; and here too the latter has 

 apparently acted as the model for the former ; inasmuch as in 

 the allied Thyridia cedesia, the area in question is divided by 

 a heavily marked band. 



Finally, the facts of geographical distribution entirely sup- 

 port the conclusion that the transparent species of Eutresis are 

 mimics of Ituna phenarete and not of /. ilione. The latter is an 

 eastern and southern species: of 16 examples in the British 

 Museum, 2 are from Rio, 2 from Minas Geraes, 3 from Brazil, 

 2 from S. Brazil, and 7 from Paraguay. /. p>he7iarete, on the 

 other hand, is a western species : of 15 examples, 10 are from 

 Bolivia, 3 from Peru, 1 from Ecuador and 1 from Tabatinga 

 (Amazons). The three examples of Eutresis imitatrix and all 

 of E. hyspa are from Ecuador, while the single undescribed 

 form is from Peru. 

 xiii] 



Mimetic Relation of Nychitona and Pseudopontia. — 

 Dr. F. A. DiXEY exhibited specimens of Nychitona medusa, 

 Cram., and Pseudojmntia 2)ci'>'Ccdoxa, Feld., observing that a 

 former suggestion of his as to a mimetic relation between them 

 (see Proc. Ent. Soc. Lond., 1906, pp. Ixix-lxxi) had been con- 

 firmed by a letter lately received from Mr. S. A. Neave, at 

 present in the Congo State, who wrote that the two forms 

 " inhabit exactly the same localities and are barely distin- 

 guishable from each other on the wing." 



Papers. 

 Mr. Guy A. K. Marshall read a paper entitled " On 



