March, ISTS] 217 



NOTES ON SEXUAL DIMOEPHISM IX EREBIA 3IEDEA. 

 BT H, GOSS, F.L.S. 



I believe attention was first called to the occurrence of two forms 

 of tlie female of Erelia Medea by Mr. Greorge "WaileS; in the Entomo- 

 logical Magazine. In a paper at p. 39 of the first volume of that 

 journal, on the insects found in Castle Eden Dene and its vicinity, 

 Mr. Wailes says : — " AVith regard to Hipparchia Ulandina^'' (^Evehia 

 Medea) " I may observe that it is somewhat singular that the males 

 " never have the broad brown band on the posterior wings instead of 

 " the bluish ash one, whilst the females may be considered as divided 

 "into two great varieties, equally common, distinguishable not only by 

 " the colour of that fascia, but by the greater distinctness of the ocelli, 

 " which, in the variety -n, Stephens (that with the bluish ash fascia, 

 "which I conceive should have been the typical variety),' are rather 

 " obscure, and approach, in appearance, those of the males." 



All the British specimens of E. Medea with which I am acquainted, 

 have been caught in Silverdale, near Carnforth, Lancashire, from which 

 locality I have, through the kindness of James Murton, Esq., received 

 specimens nearly every August during the last sixteen years. 



The specimens from this locality include both forms of the female 

 mentioned by Mr. Wailes, which are found fljing together at the 

 same time of the year, and one form seems quite as common as the other. 



The difference between these two forms is chiefly observable on 

 the under-side. 



I will first call attention to the peculiarities in what I believe to 

 be tlie second or diverging form. In this form the under-side of the 

 fore wings is tinged with fulvous, between the base and the band, as 

 in the European species Erehia iVeon(?as, and the ocelli, of which there 

 are almost invariably four in each wing, are more clearly defined than 

 in the other form, wherein they " approach in appearance," as Mr. 

 Wailes observes, " those of the males." 



In the hind-wing, which in this species is divided into what New- 

 man styles four "compartments," the third "compartment," or as I 

 should term it, the discal band, is ochreous-brown, or in some speci- 

 mens whitish-ochreous, and in this band are a few very indistinct and 

 minute white dots. 



The other form of the female, or that which more nearly approaches 

 in appearance that of the male, differs from the form before described 

 in the following particulars : the under-side of the front wing is less 

 strongly tinged with fulvous between the base and the band ; the third 

 (from the costa) of the ocelli in the marginal band is almost invariably 



